[PATCH v6 00/28] NT synchronization primitive driver

[Elizabeth Figura]

This patch series implements a new char misc driver, /dev/ntsync, which is used
to implement Windows NT synchronization primitives.

NT synchronization primitives are unique in that the wait functions both are
vectored, operate on multiple types of object with different behaviour (mutex,
semaphore, event), and affect the state of the objects they wait on. This model
is not compatible with existing kernel synchronization objects or interfaces,
and therefore the ntsync driver implements its own wait queues and locking.

This patch series is rebased against the "char-misc-next" branch of
gregkh/char-misc.git.

== Background ==

The Wine project emulates the Windows API in user space. One particular part of
that API, namely the NT synchronization primitives, have historically been
implemented via RPC to a dedicated "kernel" process. However, more recent
applications use these APIs more strenuously, and the overhead of RPC has become
a bottleneck.

The NT synchronization APIs are too complex to implement on top of existing
primitives without sacrificing correctness. Certain operations, such as
NtPulseEvent() or the "wait-for-all" mode of NtWaitForMultipleObjects(), require
direct control over the underlying wait queue, and implementing a wait queue
sufficiently robust for Wine in user space is not possible. This proposed
driver, therefore, implements the problematic interfaces directly in the Linux
kernel.

This driver was presented at Linux Plumbers Conference 2023. For those further
interested in the history of synchronization in Wine and past attempts to solve
this problem in user space, a recording of the presentation can be viewed here:

https://www.youtube.com/watch?v=NjU4nyWyhU8

== Performance ==

The performance measurements described below are copied from earlier versions of
the patch set. While some of the code has changed, I do not currently anticipate
that it has changed drastically enough to affect those measurements.

The gain in performance varies wildly depending on the application in question
and the user's hardware. For some games NT synchronization is not a bottleneck
and no change can be observed, but for others frame rate improvements of 50 to
150 percent are not atypical. The following table lists frame rate measurements
from a variety of games on a variety of hardware, taken by users Dmitry
Skvortsov, FuzzyQuils, OnMars, and myself:

Game                            Upstream        ntsync          improvement
===========================================================================
Anger Foot                       69              99              43%
Call of Juarez                   99.8           224.1           125%
Dirt 3                          110.6           860.7           678%
Forza Horizon 5                 108             160              48%
Lara Croft: Temple of Osiris    141             326             131%
Metro 2033                      164.4           199.2            21%
Resident Evil 2                  26              77             196%
The Crew                         26              51              96%
Tiny Tina's Wonderlands         130             360             177%
Total War Saga: Troy            109             146              34%
===========================================================================

== Patches ==

The intended semantics of the patches are broadly intended to match those of the
corresponding Windows functions. For those not already familiar with the Windows
functions (or their undocumented behaviour), patch 27/28 provides a detailed
specification, and individual patches also include a brief description of the
API they are implementing.

The patches making use of this driver in Wine can be retrieved or browsed here:

https://repo.or.cz/wine/zf.git/shortlog/refs/heads/ntsync5

== Previous versions ==

No changes were made from v5 other than rebasing on top of the 6.13-rc1
char-misc-next tree.

I would like to repeat a question from the last round of review, though. Two
changes were suggested related to API design, which I did not make because the
APIs in question were already released in upstream Linux. However, the driver is
also completely nonfunctional and hidden behind BROKEN, so would this be
acceptable anyway? The changes in question are:

* rename NTSYNC_IOC_SEM_POST to NTSYNC_IOC_SEM_RELEASE (matching the NT
  terminology instead of POSIX),

* change object creation ioctls to return the fds directly in the return value
  instead of through the args struct. I would also still appreciate a
  clarification on the advice in [1], which is why I didn't do this in the first
  place.

[1] https://docs.kernel.org/driver-api/ioctl.html#return-code

* Link to v5: https://lore.kernel.org/lkml/[e-mail]...
* Link to v4: https://lore.kernel.org/lkml/[e-mail]...
* Link to v3: https://lore.kernel.org/lkml/[e-mail]...
* Link to v2: https://lore.kernel.org/lkml/[e-mail]/
* Link to v1: https://lore.kernel.org/lkml/[e-mail]/
* Link to RFC v2: https://lore.kernel.org/lkml/[e-mail]/
* Link to RFC v1: https://lore.kernel.org/lkml/[e-mail]/

Elizabeth Figura (28):
  ntsync: Introduce NTSYNC_IOC_WAIT_ANY.
  ntsync: Introduce NTSYNC_IOC_WAIT_ALL.
  ntsync: Introduce NTSYNC_IOC_CREATE_MUTEX.
  ntsync: Introduce NTSYNC_IOC_MUTEX_UNLOCK.
  ntsync: Introduce NTSYNC_IOC_MUTEX_KILL.
  ntsync: Introduce NTSYNC_IOC_CREATE_EVENT.
  ntsync: Introduce NTSYNC_IOC_EVENT_SET.
  ntsync: Introduce NTSYNC_IOC_EVENT_RESET.
  ntsync: Introduce NTSYNC_IOC_EVENT_PULSE.
  ntsync: Introduce NTSYNC_IOC_SEM_READ.
  ntsync: Introduce NTSYNC_IOC_MUTEX_READ.
  ntsync: Introduce NTSYNC_IOC_EVENT_READ.
  ntsync: Introduce alertable waits.
  selftests: ntsync: Add some tests for semaphore state.
  selftests: ntsync: Add some tests for mutex state.
  selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ANY.
  selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ALL.
  selftests: ntsync: Add some tests for wakeup signaling with
    WINESYNC_IOC_WAIT_ANY.
  selftests: ntsync: Add some tests for wakeup signaling with
    WINESYNC_IOC_WAIT_ALL.
  selftests: ntsync: Add some tests for manual-reset event state.
  selftests: ntsync: Add some tests for auto-reset event state.
  selftests: ntsync: Add some tests for wakeup signaling with events.
  selftests: ntsync: Add tests for alertable waits.
  selftests: ntsync: Add some tests for wakeup signaling via alerts.
  selftests: ntsync: Add a stress test for contended waits.
  maintainers: Add an entry for ntsync.
  docs: ntsync: Add documentation for the ntsync uAPI.
  ntsync: No longer depend on BROKEN.

Documentation/userspace-api/index.rst         |    1 +
 Documentation/userspace-api/ntsync.rst        |  398 +++++
 MAINTAINERS                                   |    9 +
 drivers/misc/Kconfig                          |    1 -
 drivers/misc/ntsync.c                         |  989 +++++++++++-
 include/uapi/linux/ntsync.h                   |   39 +
 tools/testing/selftests/Makefile              |    1 +
 .../selftests/drivers/ntsync/.gitignore       |    1 +
 .../testing/selftests/drivers/ntsync/Makefile |    7 +
 tools/testing/selftests/drivers/ntsync/config |    1 +
 .../testing/selftests/drivers/ntsync/ntsync.c | 1407 +++++++++++++++++
 11 files changed, 2850 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/userspace-api/ntsync.rst
 create mode 100644 tools/testing/selftests/drivers/ntsync/.gitignore
 create mode 100644 tools/testing/selftests/drivers/ntsync/Makefile
 create mode 100644 tools/testing/selftests/drivers/ntsync/config
 create mode 100644 tools/testing/selftests/drivers/ntsync/ntsync.c

base-commit: cdd30ebb1b9f36159d66f088b61aee264e649d7a

[PATCH v6 01/28] ntsync: Introduce NTSYNC_IOC_WAIT_ANY.

[Elizabeth Figura]

This corresponds to part of the functionality of the NT syscall
NtWaitForMultipleObjects(). Specifically, it implements the behaviour where
the third argument (wait_any) is TRUE, and it does not handle alertable waits.
Those features have been split out into separate patches to ease review.

This patch therefore implements the wait/wake infrastructure which comprises the
core of ntsync's functionality.

NTSYNC_IOC_WAIT_ANY is a vectored wait function similar to poll(). Unlike
poll(), it "consumes" objects when they are signaled. For semaphores, this means
decreasing one from the internal counter. At most one object can be consumed by
this function.

This wait/wake model is fundamentally different from that used anywhere else in
the kernel, and for that reason ntsync does not use any existing infrastructure,
such as futexes, kernel mutexes or semaphores, or wait_event().

Up to 64 objects can be waited on at once. As soon as one is signaled, the
object with the lowest index is consumed, and that index is returned via the
"index" field.

A timeout is supported. The timeout is passed as a u64 nanosecond value, which
represents absolute time measured against either the MONOTONIC or REALTIME clock
(controlled by the flags argument). If U64_MAX is passed, the ioctl waits
indefinitely.

This ioctl validates that all objects belong to the relevant device. This is not
necessary for any technical reason related to NTSYNC_IOC_WAIT_ANY, but will be
necessary for NTSYNC_IOC_WAIT_ALL introduced in the following patch.

Some padding fields are added for alignment and for fields which will be added
in future patches (split out to ease review).

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 245 ++++++++++++++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  14 +++
 2 files changed, 259 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 4954553b7baa..2bfe5299f25b 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -6,11 +6,16 @@
  */

#include <linux/anon_inodes.h>
+#include <linux/atomic.h>
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/hrtimer.h>
+#include <linux/ktime.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/overflow.h>
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <uapi/linux/ntsync.h>
@@ -30,6 +35,8 @@ enum ntsync_type {
  *
  * Both rely on struct file for reference counting. Individual
  * ntsync_obj objects take a reference to the device when created.
+ * Wait operations take a reference to each object being waited on for
+ * the duration of the wait.
  */

struct ntsync_obj {
@@ -47,12 +54,55 @@ struct ntsync_obj {
    		__u32 max;
    	} sem;
    } u;
+
+	struct list_head any_waiters;
+};
+
+struct ntsync_q_entry {
+	struct list_head node;
+	struct ntsync_q *q;
+	struct ntsync_obj *obj;
+	__u32 index;
+};
+
+struct ntsync_q {
+	struct task_struct *task;
+
+	/*
+	 * Protected via atomic_try_cmpxchg(). Only the thread that wins the
+	 * compare-and-swap may actually change object states and wake this
+	 * task.
+	 */
+	atomic_t signaled;
+
+	__u32 count;
+	struct ntsync_q_entry entries[];
 };

struct ntsync_device {
    struct file *file;
 };

+static void try_wake_any_sem(struct ntsync_obj *sem)
+{
+	struct ntsync_q_entry *entry;
+
+	lockdep_assert_held(&sem->lock);
+
+	list_for_each_entry(entry, &sem->any_waiters, node) {
+		struct ntsync_q *q = entry->q;
+		int signaled = -1;
+
+		if (!sem->u.sem.count)
+			break;
+
+		if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) {
+			sem->u.sem.count--;
+			wake_up_process(q->task);
+		}
+	}
+}
+
 /*
  * Actually change the semaphore state, returning -EOVERFLOW if it is made
  * invalid.
@@ -88,6 +138,8 @@ static int ntsync_sem_post(struct ntsync_obj *sem, void __user *argp)

prev_count = sem->u.sem.count;
    ret = post_sem_state(sem, args);
+	if (!ret)
+		try_wake_any_sem(sem);

spin_unlock(&sem->lock);

@@ -140,6 +192,7 @@ static struct ntsync_obj *ntsync_alloc_obj(struct ntsync_device *dev,
    obj->dev = dev;
    get_file(dev->file);
    spin_lock_init(&obj->lock);
+	INIT_LIST_HEAD(&obj->any_waiters);

return obj;
 }
@@ -190,6 +243,196 @@ static int ntsync_create_sem(struct ntsync_device *dev, void __user *argp)
    return put_user(fd, &user_args->sem);
 }

+static struct ntsync_obj *get_obj(struct ntsync_device *dev, int fd)
+{
+	struct file *file = fget(fd);
+	struct ntsync_obj *obj;
+
+	if (!file)
+		return NULL;
+
+	if (file->f_op != &ntsync_obj_fops) {
+		fput(file);
+		return NULL;
+	}
+
+	obj = file->private_data;
+	if (obj->dev != dev) {
+		fput(file);
+		return NULL;
+	}
+
+	return obj;
+}
+
+static void put_obj(struct ntsync_obj *obj)
+{
+	fput(obj->file);
+}
+
+static int ntsync_schedule(const struct ntsync_q *q, const struct ntsync_wait_args *args)
+{
+	ktime_t timeout = ns_to_ktime(args->timeout);
+	clockid_t clock = CLOCK_MONOTONIC;
+	ktime_t *timeout_ptr;
+	int ret = 0;
+
+	timeout_ptr = (args->timeout == U64_MAX ? NULL : &timeout);
+
+	if (args->flags & NTSYNC_WAIT_REALTIME)
+		clock = CLOCK_REALTIME;
+
+	do {
+		if (signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (atomic_read(&q->signaled) != -1) {
+			ret = 0;
+			break;
+		}
+		ret = schedule_hrtimeout_range_clock(timeout_ptr, 0, HRTIMER_MODE_ABS, clock);
+	} while (ret < 0);
+	__set_current_state(TASK_RUNNING);
+
+	return ret;
+}
+
+/*
+ * Allocate and initialize the ntsync_q structure, but do not queue us yet.
+ */
+static int setup_wait(struct ntsync_device *dev,
+		      const struct ntsync_wait_args *args,
+		      struct ntsync_q **ret_q)
+{
+	const __u32 count = args->count;
+	int fds[NTSYNC_MAX_WAIT_COUNT];
+	struct ntsync_q *q;
+	__u32 i, j;
+
+	if (args->pad[0] || args->pad[1] || args->pad[2] || (args->flags & ~NTSYNC_WAIT_REALTIME))
+		return -EINVAL;
+
+	if (args->count > NTSYNC_MAX_WAIT_COUNT)
+		return -EINVAL;
+
+	if (copy_from_user(fds, u64_to_user_ptr(args->objs),
+			   array_size(count, sizeof(*fds))))
+		return -EFAULT;
+
+	q = kmalloc(struct_size(q, entries, count), GFP_KERNEL);
+	if (!q)
+		return -ENOMEM;
+	q->task = current;
+	atomic_set(&q->signaled, -1);
+	q->count = count;
+
+	for (i = 0; i < count; i++) {
+		struct ntsync_q_entry *entry = &q->entries[i];
+		struct ntsync_obj *obj = get_obj(dev, fds[i]);
+
+		if (!obj)
+			goto err;
+
+		entry->obj = obj;
+		entry->q = q;
+		entry->index = i;
+	}
+
+	*ret_q = q;
+	return 0;
+
+err:
+	for (j = 0; j < i; j++)
+		put_obj(q->entries[j].obj);
+	kfree(q);
+	return -EINVAL;
+}
+
+static void try_wake_any_obj(struct ntsync_obj *obj)
+{
+	switch (obj->type) {
+	case NTSYNC_TYPE_SEM:
+		try_wake_any_sem(obj);
+		break;
+	}
+}
+
+static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
+{
+	struct ntsync_wait_args args;
+	struct ntsync_q *q;
+	int signaled;
+	__u32 i;
+	int ret;
+
+	if (copy_from_user(&args, argp, sizeof(args)))
+		return -EFAULT;
+
+	ret = setup_wait(dev, &args, &q);
+	if (ret < 0)
+		return ret;
+
+	/* queue ourselves */
+
+	for (i = 0; i < args.count; i++) {
+		struct ntsync_q_entry *entry = &q->entries[i];
+		struct ntsync_obj *obj = entry->obj;
+
+		spin_lock(&obj->lock);
+		list_add_tail(&entry->node, &obj->any_waiters);
+		spin_unlock(&obj->lock);
+	}
+
+	/* check if we are already signaled */
+
+	for (i = 0; i < args.count; i++) {
+		struct ntsync_obj *obj = q->entries[i].obj;
+
+		if (atomic_read(&q->signaled) != -1)
+			break;
+
+		spin_lock(&obj->lock);
+		try_wake_any_obj(obj);
+		spin_unlock(&obj->lock);
+	}
+
+	/* sleep */
+
+	ret = ntsync_schedule(q, &args);
+
+	/* and finally, unqueue */
+
+	for (i = 0; i < args.count; i++) {
+		struct ntsync_q_entry *entry = &q->entries[i];
+		struct ntsync_obj *obj = entry->obj;
+
+		spin_lock(&obj->lock);
+		list_del(&entry->node);
+		spin_unlock(&obj->lock);
+
+		put_obj(obj);
+	}
+
+	signaled = atomic_read(&q->signaled);
+	if (signaled != -1) {
+		struct ntsync_wait_args __user *user_args = argp;
+
+		/* even if we caught a signal, we need to communicate success */
+		ret = 0;
+
+		if (put_user(signaled, &user_args->index))
+			ret = -EFAULT;
+	} else if (!ret) {
+		ret = -ETIMEDOUT;
+	}
+
+	kfree(q);
+	return ret;
+}
+
 static int ntsync_char_open(struct inode *inode, struct file *file)
 {
    struct ntsync_device *dev;
@@ -221,6 +464,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
    switch (cmd) {
    case NTSYNC_IOC_CREATE_SEM:
    	return ntsync_create_sem(dev, argp);
+	case NTSYNC_IOC_WAIT_ANY:
+		return ntsync_wait_any(dev, argp);
    default:
    	return -ENOIOCTLCMD;
    }
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index dcfa38fdc93c..edc12c7a10dc 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -16,7 +16,21 @@ struct ntsync_sem_args {
    __u32 max;
 };

+#define NTSYNC_WAIT_REALTIME	0x1
+
+struct ntsync_wait_args {
+	__u64 timeout;
+	__u64 objs;
+	__u32 count;
+	__u32 index;
+	__u32 flags;
+	__u32 pad[3];
+};
+
+#define NTSYNC_MAX_WAIT_COUNT 64
+
 #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_SEM_POST		_IOWR('N', 0x81, __u32)

[PATCH v6 02/28] ntsync: Introduce NTSYNC_IOC_WAIT_ALL.

[Elizabeth Figura]

This is similar to NTSYNC_IOC_WAIT_ANY, but waits until all of the objects are
simultaneously signaled, and then acquires all of them as a single atomic
operation.

Because acquisition of multiple objects is atomic, some complex locking is
required. We cannot simply spin-lock multiple objects simultaneously, as that
may disable preëmption for a problematically long time.

Instead, modifying any object which may be involved in a wait-all operation takes
a device-wide sleeping mutex, "wait_all_lock", instead of the normal object
spinlock.

Because wait-for-all is a rare operation, in order to optimize wait-for-any,
this lock is only taken when necessary. "all_hint" is used to mark objects which
are involved in a wait-for-all operation, and if an object is not, only its
spinlock is taken.

The locking scheme used here was written by Peter Zijlstra.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 334 ++++++++++++++++++++++++++++++++++--
 include/uapi/linux/ntsync.h |   1 +
 2 files changed, 322 insertions(+), 13 deletions(-)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 2bfe5299f25b..0f4da571fa33 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -13,6 +13,7 @@
 #include <linux/ktime.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/overflow.h>
 #include <linux/sched.h>
 #include <linux/sched/signal.h>
@@ -41,6 +42,7 @@ enum ntsync_type {

struct ntsync_obj {
    spinlock_t lock;
+	int dev_locked;

enum ntsync_type type;

@@ -55,7 +57,30 @@ struct ntsync_obj {
    	} sem;
    } u;

+	/*
+	 * any_waiters is protected by the object lock, but all_waiters is
+	 * protected by the device wait_all_lock.
+	 */
    struct list_head any_waiters;
+	struct list_head all_waiters;
+
+	/*
+	 * Hint describing how many tasks are queued on this object in a
+	 * wait-all operation.
+	 *
+	 * Any time we do a wake, we may need to wake "all" waiters as well as
+	 * "any" waiters. In order to atomically wake "all" waiters, we must
+	 * lock all of the objects, and that means grabbing the wait_all_lock
+	 * below (and, due to lock ordering rules, before locking this object).
+	 * However, wait-all is a rare operation, and grabbing the wait-all
+	 * lock for every wake would create unnecessary contention.
+	 * Therefore we first check whether all_hint is zero, and, if it is,
+	 * we skip trying to wake "all" waiters.
+	 *
+	 * Since wait requests must originate from user-space threads, we're
+	 * limited here by PID_MAX_LIMIT, so there's no risk of overflow.
+	 */
+	atomic_t all_hint;
 };

struct ntsync_q_entry {
@@ -75,19 +100,198 @@ struct ntsync_q {
     */
    atomic_t signaled;

+	bool all;
    __u32 count;
    struct ntsync_q_entry entries[];
 };

struct ntsync_device {
+	/*
+	 * Wait-all operations must atomically grab all objects, and be totally
+	 * ordered with respect to each other and wait-any operations.
+	 * If one thread is trying to acquire several objects, another thread
+	 * cannot touch the object at the same time.
+	 *
+	 * This device-wide lock is used to serialize wait-for-all
+	 * operations, and operations on an object that is involved in a
+	 * wait-for-all.
+	 */
+	struct mutex wait_all_lock;
+
    struct file *file;
 };

+/*
+ * Single objects are locked using obj->lock.
+ *
+ * Multiple objects are 'locked' while holding dev->wait_all_lock.
+ * In this case however, individual objects are not locked by holding
+ * obj->lock, but by setting obj->dev_locked.
+ *
+ * This means that in order to lock a single object, the sequence is slightly
+ * more complicated than usual. Specifically it needs to check obj->dev_locked
+ * after acquiring obj->lock, if set, it needs to drop the lock and acquire
+ * dev->wait_all_lock in order to serialize against the multi-object operation.
+ */
+
+static void dev_lock_obj(struct ntsync_device *dev, struct ntsync_obj *obj)
+{
+	lockdep_assert_held(&dev->wait_all_lock);
+	lockdep_assert(obj->dev == dev);
+	spin_lock(&obj->lock);
+	/*
+	 * By setting obj->dev_locked inside obj->lock, it is ensured that
+	 * anyone holding obj->lock must see the value.
+	 */
+	obj->dev_locked = 1;
+	spin_unlock(&obj->lock);
+}
+
+static void dev_unlock_obj(struct ntsync_device *dev, struct ntsync_obj *obj)
+{
+	lockdep_assert_held(&dev->wait_all_lock);
+	lockdep_assert(obj->dev == dev);
+	spin_lock(&obj->lock);
+	obj->dev_locked = 0;
+	spin_unlock(&obj->lock);
+}
+
+static void obj_lock(struct ntsync_obj *obj)
+{
+	struct ntsync_device *dev = obj->dev;
+
+	for (;;) {
+		spin_lock(&obj->lock);
+		if (likely(!obj->dev_locked))
+			break;
+
+		spin_unlock(&obj->lock);
+		mutex_lock(&dev->wait_all_lock);
+		spin_lock(&obj->lock);
+		/*
+		 * obj->dev_locked should be set and released under the same
+		 * wait_all_lock section, since we now own this lock, it should
+		 * be clear.
+		 */
+		lockdep_assert(!obj->dev_locked);
+		spin_unlock(&obj->lock);
+		mutex_unlock(&dev->wait_all_lock);
+	}
+}
+
+static void obj_unlock(struct ntsync_obj *obj)
+{
+	spin_unlock(&obj->lock);
+}
+
+static bool ntsync_lock_obj(struct ntsync_device *dev, struct ntsync_obj *obj)
+{
+	bool all;
+
+	obj_lock(obj);
+	all = atomic_read(&obj->all_hint);
+	if (unlikely(all)) {
+		obj_unlock(obj);
+		mutex_lock(&dev->wait_all_lock);
+		dev_lock_obj(dev, obj);
+	}
+
+	return all;
+}
+
+static void ntsync_unlock_obj(struct ntsync_device *dev, struct ntsync_obj *obj, bool all)
+{
+	if (all) {
+		dev_unlock_obj(dev, obj);
+		mutex_unlock(&dev->wait_all_lock);
+	} else {
+		obj_unlock(obj);
+	}
+}
+
+#define ntsync_assert_held(obj) \
+	lockdep_assert((lockdep_is_held(&(obj)->lock) != LOCK_STATE_NOT_HELD) || \
+		       ((lockdep_is_held(&(obj)->dev->wait_all_lock) != LOCK_STATE_NOT_HELD) && \
+			(obj)->dev_locked))
+
+static bool is_signaled(struct ntsync_obj *obj)
+{
+	ntsync_assert_held(obj);
+
+	switch (obj->type) {
+	case NTSYNC_TYPE_SEM:
+		return !!obj->u.sem.count;
+	}
+
+	WARN(1, "bad object type %#x\n", obj->type);
+	return false;
+}
+
+/*
+ * "locked_obj" is an optional pointer to an object which is already locked and
+ * should not be locked again. This is necessary so that changing an object's
+ * state and waking it can be a single atomic operation.
+ */
+static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q,
+			 struct ntsync_obj *locked_obj)
+{
+	__u32 count = q->count;
+	bool can_wake = true;
+	int signaled = -1;
+	__u32 i;
+
+	lockdep_assert_held(&dev->wait_all_lock);
+	if (locked_obj)
+		lockdep_assert(locked_obj->dev_locked);
+
+	for (i = 0; i < count; i++) {
+		if (q->entries[i].obj != locked_obj)
+			dev_lock_obj(dev, q->entries[i].obj);
+	}
+
+	for (i = 0; i < count; i++) {
+		if (!is_signaled(q->entries[i].obj)) {
+			can_wake = false;
+			break;
+		}
+	}
+
+	if (can_wake && atomic_try_cmpxchg(&q->signaled, &signaled, 0)) {
+		for (i = 0; i < count; i++) {
+			struct ntsync_obj *obj = q->entries[i].obj;
+
+			switch (obj->type) {
+			case NTSYNC_TYPE_SEM:
+				obj->u.sem.count--;
+				break;
+			}
+		}
+		wake_up_process(q->task);
+	}
+
+	for (i = 0; i < count; i++) {
+		if (q->entries[i].obj != locked_obj)
+			dev_unlock_obj(dev, q->entries[i].obj);
+	}
+}
+
+static void try_wake_all_obj(struct ntsync_device *dev, struct ntsync_obj *obj)
+{
+	struct ntsync_q_entry *entry;
+
+	lockdep_assert_held(&dev->wait_all_lock);
+	lockdep_assert(obj->dev_locked);
+
+	list_for_each_entry(entry, &obj->all_waiters, node)
+		try_wake_all(dev, entry->q, obj);
+}
+
 static void try_wake_any_sem(struct ntsync_obj *sem)
 {
    struct ntsync_q_entry *entry;

-	lockdep_assert_held(&sem->lock);
+	ntsync_assert_held(sem);
+	lockdep_assert(sem->type == NTSYNC_TYPE_SEM);

list_for_each_entry(entry, &sem->any_waiters, node) {
    	struct ntsync_q *q = entry->q;
@@ -111,7 +315,7 @@ static int post_sem_state(struct ntsync_obj *sem, __u32 count)
 {
    __u32 sum;

-	lockdep_assert_held(&sem->lock);
+	ntsync_assert_held(sem);

if (check_add_overflow(sem->u.sem.count, count, &sum) ||
        sum > sem->u.sem.max)
@@ -123,9 +327,11 @@ static int post_sem_state(struct ntsync_obj *sem, __u32 count)

static int ntsync_sem_post(struct ntsync_obj *sem, void __user *argp)
 {
+	struct ntsync_device *dev = sem->dev;
    __u32 __user *user_args = argp;
    __u32 prev_count;
    __u32 args;
+	bool all;
    int ret;

if (copy_from_user(&args, argp, sizeof(args)))
@@ -134,14 +340,17 @@ static int ntsync_sem_post(struct ntsync_obj *sem, void __user *argp)
    if (sem->type != NTSYNC_TYPE_SEM)
    	return -EINVAL;

-	spin_lock(&sem->lock);
+	all = ntsync_lock_obj(dev, sem);

prev_count = sem->u.sem.count;
    ret = post_sem_state(sem, args);
-	if (!ret)
+	if (!ret) {
+		if (all)
+			try_wake_all_obj(dev, sem);
    	try_wake_any_sem(sem);
+	}

-	spin_unlock(&sem->lock);
+	ntsync_unlock_obj(dev, sem, all);

if (!ret && put_user(prev_count, user_args))
    	ret = -EFAULT;
@@ -193,6 +402,8 @@ static struct ntsync_obj *ntsync_alloc_obj(struct ntsync_device *dev,
    get_file(dev->file);
    spin_lock_init(&obj->lock);
    INIT_LIST_HEAD(&obj->any_waiters);
+	INIT_LIST_HEAD(&obj->all_waiters);
+	atomic_set(&obj->all_hint, 0);

return obj;
 }
@@ -304,7 +515,7 @@ static int ntsync_schedule(const struct ntsync_q *q, const struct ntsync_wait_ar
  * Allocate and initialize the ntsync_q structure, but do not queue us yet.
  */
 static int setup_wait(struct ntsync_device *dev,
-		      const struct ntsync_wait_args *args,
+		      const struct ntsync_wait_args *args, bool all,
    	      struct ntsync_q **ret_q)
 {
    const __u32 count = args->count;
@@ -327,6 +538,7 @@ static int setup_wait(struct ntsync_device *dev,
    	return -ENOMEM;
    q->task = current;
    atomic_set(&q->signaled, -1);
+	q->all = all;
    q->count = count;

for (i = 0; i < count; i++) {
@@ -336,6 +548,16 @@ static int setup_wait(struct ntsync_device *dev,
    	if (!obj)
    		goto err;

+		if (all) {
+			/* Check that the objects are all distinct. */
+			for (j = 0; j < i; j++) {
+				if (obj == q->entries[j].obj) {
+					put_obj(obj);
+					goto err;
+				}
+			}
+		}
+
    	entry->obj = obj;
    	entry->q = q;
    	entry->index = i;
@@ -365,13 +587,14 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    struct ntsync_wait_args args;
    struct ntsync_q *q;
    int signaled;
+	bool all;
    __u32 i;
    int ret;

if (copy_from_user(&args, argp, sizeof(args)))
    	return -EFAULT;

-	ret = setup_wait(dev, &args, &q);
+	ret = setup_wait(dev, &args, false, &q);
    if (ret < 0)
    	return ret;

@@ -381,9 +604,9 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    	struct ntsync_q_entry *entry = &q->entries[i];
    	struct ntsync_obj *obj = entry->obj;

-		spin_lock(&obj->lock);
+		all = ntsync_lock_obj(dev, obj);
    	list_add_tail(&entry->node, &obj->any_waiters);
-		spin_unlock(&obj->lock);
+		ntsync_unlock_obj(dev, obj, all);
    }

/* check if we are already signaled */
@@ -394,9 +617,9 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    	if (atomic_read(&q->signaled) != -1)
    		break;

-		spin_lock(&obj->lock);
+		all = ntsync_lock_obj(dev, obj);
    	try_wake_any_obj(obj);
-		spin_unlock(&obj->lock);
+		ntsync_unlock_obj(dev, obj, all);
    }

/* sleep */
@@ -409,9 +632,9 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    	struct ntsync_q_entry *entry = &q->entries[i];
    	struct ntsync_obj *obj = entry->obj;

-		spin_lock(&obj->lock);
+		all = ntsync_lock_obj(dev, obj);
    	list_del(&entry->node);
-		spin_unlock(&obj->lock);
+		ntsync_unlock_obj(dev, obj, all);

put_obj(obj);
    }
@@ -433,6 +656,87 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    return ret;
 }

+static int ntsync_wait_all(struct ntsync_device *dev, void __user *argp)
+{
+	struct ntsync_wait_args args;
+	struct ntsync_q *q;
+	int signaled;
+	__u32 i;
+	int ret;
+
+	if (copy_from_user(&args, argp, sizeof(args)))
+		return -EFAULT;
+
+	ret = setup_wait(dev, &args, true, &q);
+	if (ret < 0)
+		return ret;
+
+	/* queue ourselves */
+
+	mutex_lock(&dev->wait_all_lock);
+
+	for (i = 0; i < args.count; i++) {
+		struct ntsync_q_entry *entry = &q->entries[i];
+		struct ntsync_obj *obj = entry->obj;
+
+		atomic_inc(&obj->all_hint);
+
+		/*
+		 * obj->all_waiters is protected by dev->wait_all_lock rather
+		 * than obj->lock, so there is no need to acquire obj->lock
+		 * here.
+		 */
+		list_add_tail(&entry->node, &obj->all_waiters);
+	}
+
+	/* check if we are already signaled */
+
+	try_wake_all(dev, q, NULL);
+
+	mutex_unlock(&dev->wait_all_lock);
+
+	/* sleep */
+
+	ret = ntsync_schedule(q, &args);
+
+	/* and finally, unqueue */
+
+	mutex_lock(&dev->wait_all_lock);
+
+	for (i = 0; i < args.count; i++) {
+		struct ntsync_q_entry *entry = &q->entries[i];
+		struct ntsync_obj *obj = entry->obj;
+
+		/*
+		 * obj->all_waiters is protected by dev->wait_all_lock rather
+		 * than obj->lock, so there is no need to acquire it here.
+		 */
+		list_del(&entry->node);
+
+		atomic_dec(&obj->all_hint);
+
+		put_obj(obj);
+	}
+
+	mutex_unlock(&dev->wait_all_lock);
+
+	signaled = atomic_read(&q->signaled);
+	if (signaled != -1) {
+		struct ntsync_wait_args __user *user_args = argp;
+
+		/* even if we caught a signal, we need to communicate success */
+		ret = 0;
+
+		if (put_user(signaled, &user_args->index))
+			ret = -EFAULT;
+	} else if (!ret) {
+		ret = -ETIMEDOUT;
+	}
+
+	kfree(q);
+	return ret;
+}
+
 static int ntsync_char_open(struct inode *inode, struct file *file)
 {
    struct ntsync_device *dev;
@@ -441,6 +745,8 @@ static int ntsync_char_open(struct inode *inode, struct file *file)
    if (!dev)
    	return -ENOMEM;

+	mutex_init(&dev->wait_all_lock);
+
    file->private_data = dev;
    dev->file = file;
    return nonseekable_open(inode, file);
@@ -464,6 +770,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
    switch (cmd) {
    case NTSYNC_IOC_CREATE_SEM:
    	return ntsync_create_sem(dev, argp);
+	case NTSYNC_IOC_WAIT_ALL:
+		return ntsync_wait_all(dev, argp);
    case NTSYNC_IOC_WAIT_ANY:
    	return ntsync_wait_any(dev, argp);
    default:
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index edc12c7a10dc..addf187b1573 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -31,6 +31,7 @@ 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_SEM_POST		_IOWR('N', 0x81, __u32)

[PATCH v6 03/28] ntsync: Introduce NTSYNC_IOC_CREATE_MUTEX.

[Elizabeth Figura]

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. The 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 passed
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 0f4da571fa33..30c0bbb442da 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -25,6 +25,7 @@

enum ntsync_type {
    NTSYNC_TYPE_SEM,
+	NTSYNC_TYPE_MUTEX,
 };

/*
@@ -55,6 +56,10 @@ struct ntsync_obj {
    		__u32 count;
    		__u32 max;
    	} sem;
+		struct {
+			__u32 count;
+			pid_t owner;
+		} mutex;
    } u;

/*
@@ -92,6 +97,7 @@ struct ntsync_q_entry {

struct ntsync_q {
    struct task_struct *task;
+	__u32 owner;

/*
     * Protected via atomic_try_cmpxchg(). Only the thread that wins the
@@ -214,13 +220,17 @@ static void ntsync_unlock_obj(struct ntsync_device *dev, struct ntsync_obj *obj,
    	       ((lockdep_is_held(&(obj)->dev->wait_all_lock) != LOCK_STATE_NOT_HELD) && \
    		(obj)->dev_locked))

-static bool is_signaled(struct ntsync_obj *obj)
+static bool is_signaled(struct ntsync_obj *obj, __u32 owner)
 {
    ntsync_assert_held(obj);

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 != owner)
+			return false;
+		return obj->u.mutex.count < UINT_MAX;
    }

WARN(1, "bad object type %#x\n", obj->type);
@@ -250,7 +260,7 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q,
    }

for (i = 0; i < count; i++) {
-		if (!is_signaled(q->entries[i].obj)) {
+		if (!is_signaled(q->entries[i].obj, q->owner)) {
    		can_wake = false;
    		break;
    	}
@@ -264,6 +274,10 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q,
    		case NTSYNC_TYPE_SEM:
    			obj->u.sem.count--;
    			break;
+			case NTSYNC_TYPE_MUTEX:
+				obj->u.mutex.count++;
+				obj->u.mutex.owner = q->owner;
+				break;
    		}
    	}
    	wake_up_process(q->task);
@@ -307,6 +321,30 @@ static void try_wake_any_sem(struct ntsync_obj *sem)
    }
 }

+static void try_wake_any_mutex(struct ntsync_obj *mutex)
+{
+	struct ntsync_q_entry *entry;
+
+	ntsync_assert_held(mutex);
+	lockdep_assert(mutex->type == NTSYNC_TYPE_MUTEX);
+
+	list_for_each_entry(entry, &mutex->any_waiters, node) {
+		struct ntsync_q *q = entry->q;
+		int signaled = -1;
+
+		if (mutex->u.mutex.count == UINT_MAX)
+			break;
+		if (mutex->u.mutex.owner && mutex->u.mutex.owner != q->owner)
+			continue;
+
+		if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) {
+			mutex->u.mutex.count++;
+			mutex->u.mutex.owner = q->owner;
+			wake_up_process(q->task);
+		}
+	}
+}
+
 /*
  * Actually change the semaphore state, returning -EOVERFLOW if it is made
  * invalid.
@@ -454,6 +492,33 @@ static int ntsync_create_sem(struct ntsync_device *dev, void __user *argp)
    return put_user(fd, &user_args->sem);
 }

+static int ntsync_create_mutex(struct ntsync_device *dev, void __user *argp)
+{
+	struct ntsync_mutex_args __user *user_args = 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 != !args.count)
+		return -EINVAL;
+
+	mutex = ntsync_alloc_obj(dev, NTSYNC_TYPE_MUTEX);
+	if (!mutex)
+		return -ENOMEM;
+	mutex->u.mutex.count = args.count;
+	mutex->u.mutex.owner = args.owner;
+	fd = 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 = fget(fd);
@@ -523,7 +588,7 @@ static int setup_wait(struct ntsync_device *dev,
    struct ntsync_q *q;
    __u32 i, j;

-	if (args->pad[0] || args->pad[1] || args->pad[2] || (args->flags & ~NTSYNC_WAIT_REALTIME))
+	if (args->pad[0] || args->pad[1] || (args->flags & ~NTSYNC_WAIT_REALTIME))
    	return -EINVAL;

if (args->count > NTSYNC_MAX_WAIT_COUNT)
@@ -537,6 +602,7 @@ static int setup_wait(struct ntsync_device *dev,
    if (!q)
    	return -ENOMEM;
    q->task = current;
+	q->owner = args->owner;
    atomic_set(&q->signaled, -1);
    q->all = all;
    q->count = count;
@@ -579,6 +645,9 @@ 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;
    }
 }

@@ -768,6 +837,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
    void __user *argp = (void __user *)parm;

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;
 };

+struct ntsync_mutex_args {
+	__u32 mutex;
+	__u32 owner;
+	__u32 count;
+};
+
 #define NTSYNC_WAIT_REALTIME	0x1

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];
 };

#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)

#define NTSYNC_IOC_SEM_POST		_IOWR('N', 0x81, __u32)

[PATCH v6 04/28] ntsync: Introduce NTSYNC_IOC_MUTEX_UNLOCK.

[Elizabeth Figura]

This corresponds to the NT syscall NtReleaseMutant().

This syscall decrements the mutex's recursion count by one, and returns the
previous value. If the mutex is not owned by the current task, the function
instead fails and returns -EPERM.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 53 +++++++++++++++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 54 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 30c0bbb442da..6ed278c17be9 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -396,6 +396,57 @@ static int ntsync_sem_post(struct ntsync_obj *sem, void __user *argp)
    return ret;
 }

+/*
+ * Actually change the mutex state, returning -EPERM if not the owner.
+ */
+static int unlock_mutex_state(struct ntsync_obj *mutex,
+			      const struct ntsync_mutex_args *args)
+{
+	ntsync_assert_held(mutex);
+
+	if (mutex->u.mutex.owner != args->owner)
+		return -EPERM;
+
+	if (!--mutex->u.mutex.count)
+		mutex->u.mutex.owner = 0;
+	return 0;
+}
+
+static int ntsync_mutex_unlock(struct ntsync_obj *mutex, void __user *argp)
+{
+	struct ntsync_mutex_args __user *user_args = argp;
+	struct ntsync_device *dev = mutex->dev;
+	struct ntsync_mutex_args args;
+	__u32 prev_count;
+	bool all;
+	int ret;
+
+	if (copy_from_user(&args, argp, sizeof(args)))
+		return -EFAULT;
+	if (!args.owner)
+		return -EINVAL;
+
+	if (mutex->type != NTSYNC_TYPE_MUTEX)
+		return -EINVAL;
+
+	all = ntsync_lock_obj(dev, mutex);
+
+	prev_count = mutex->u.mutex.count;
+	ret = unlock_mutex_state(mutex, &args);
+	if (!ret) {
+		if (all)
+			try_wake_all_obj(dev, mutex);
+		try_wake_any_mutex(mutex);
+	}
+
+	ntsync_unlock_obj(dev, mutex, all);
+
+	if (!ret && put_user(prev_count, &user_args->count))
+		ret = -EFAULT;
+
+	return ret;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
    struct ntsync_obj *obj = file->private_data;
@@ -415,6 +466,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    switch (cmd) {
    case NTSYNC_IOC_SEM_POST:
    	return ntsync_sem_post(obj, argp);
+	case NTSYNC_IOC_MUTEX_UNLOCK:
+		return ntsync_mutex_unlock(obj, argp);
    default:
    	return -ENOIOCTLCMD;
    }
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index d5e5a2fbcb4d..a633db34f284 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -42,5 +42,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_CREATE_MUTEX		_IOWR('N', 0x84, struct ntsync_sem_args)

#define NTSYNC_IOC_SEM_POST		_IOWR('N', 0x81, __u32)
+#define NTSYNC_IOC_MUTEX_UNLOCK		_IOWR('N', 0x85, struct ntsync_mutex_args)

#endif

[PATCH v6 05/28] ntsync: Introduce NTSYNC_IOC_MUTEX_KILL.

[Elizabeth Figura]

This does not correspond to any NT syscall. Rather, when a thread dies, it
should be called by the NT emulator for each mutex, with the TID of the dying
thread.

NT mutexes are robust (in the pthread sense). When an NT thread dies, any
mutexes it owned are immediately released. Acquisition of those mutexes by other
threads will return a special value indicating that the mutex was abandoned,
like EOWNERDEAD returned from pthread_mutex_lock(), and EOWNERDEAD is indeed
used here for that purpose.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 61 +++++++++++++++++++++++++++++++++++--
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 6ed278c17be9..0ed864d291a6 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -59,6 +59,7 @@ struct ntsync_obj {
    	struct {
    		__u32 count;
    		pid_t owner;
+			bool ownerdead;
    	} mutex;
    } u;

@@ -107,6 +108,7 @@ struct ntsync_q {
    atomic_t signaled;

bool all;
+	bool ownerdead;
    __u32 count;
    struct ntsync_q_entry entries[];
 };
@@ -275,6 +277,9 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q,
    			obj->u.sem.count--;
    			break;
    		case NTSYNC_TYPE_MUTEX:
+				if (obj->u.mutex.ownerdead)
+					q->ownerdead = true;
+				obj->u.mutex.ownerdead = false;
    			obj->u.mutex.count++;
    			obj->u.mutex.owner = q->owner;
    			break;
@@ -338,6 +343,9 @@ static void try_wake_any_mutex(struct ntsync_obj *mutex)
    		continue;

if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) {
+			if (mutex->u.mutex.ownerdead)
+				q->ownerdead = true;
+			mutex->u.mutex.ownerdead = false;
    		mutex->u.mutex.count++;
    		mutex->u.mutex.owner = q->owner;
    		wake_up_process(q->task);
@@ -447,6 +455,52 @@ static int ntsync_mutex_unlock(struct ntsync_obj *mutex, void __user *argp)
    return ret;
 }

+/*
+ * Actually change the mutex state to mark its owner as dead,
+ * returning -EPERM if not the owner.
+ */
+static int kill_mutex_state(struct ntsync_obj *mutex, __u32 owner)
+{
+	ntsync_assert_held(mutex);
+
+	if (mutex->u.mutex.owner != owner)
+		return -EPERM;
+
+	mutex->u.mutex.ownerdead = true;
+	mutex->u.mutex.owner = 0;
+	mutex->u.mutex.count = 0;
+	return 0;
+}
+
+static int ntsync_mutex_kill(struct ntsync_obj *mutex, void __user *argp)
+{
+	struct ntsync_device *dev = mutex->dev;
+	__u32 owner;
+	bool all;
+	int ret;
+
+	if (get_user(owner, (__u32 __user *)argp))
+		return -EFAULT;
+	if (!owner)
+		return -EINVAL;
+
+	if (mutex->type != NTSYNC_TYPE_MUTEX)
+		return -EINVAL;
+
+	all = ntsync_lock_obj(dev, mutex);
+
+	ret = kill_mutex_state(mutex, owner);
+	if (!ret) {
+		if (all)
+			try_wake_all_obj(dev, mutex);
+		try_wake_any_mutex(mutex);
+	}
+
+	ntsync_unlock_obj(dev, mutex, all);
+
+	return ret;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
    struct ntsync_obj *obj = file->private_data;
@@ -468,6 +522,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    	return ntsync_sem_post(obj, argp);
    case NTSYNC_IOC_MUTEX_UNLOCK:
    	return ntsync_mutex_unlock(obj, argp);
+	case NTSYNC_IOC_MUTEX_KILL:
+		return ntsync_mutex_kill(obj, argp);
    default:
    	return -ENOIOCTLCMD;
    }
@@ -658,6 +714,7 @@ static int setup_wait(struct ntsync_device *dev,
    q->owner = args->owner;
    atomic_set(&q->signaled, -1);
    q->all = all;
+	q->ownerdead = false;
    q->count = count;

for (i = 0; i < count; i++) {
@@ -766,7 +823,7 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    	struct ntsync_wait_args __user *user_args = argp;

/* even if we caught a signal, we need to communicate success */
-		ret = 0;
+		ret = q->ownerdead ? -EOWNERDEAD : 0;

if (put_user(signaled, &user_args->index))
    		ret = -EFAULT;
@@ -847,7 +904,7 @@ static int ntsync_wait_all(struct ntsync_device *dev, void __user *argp)
    	struct ntsync_wait_args __user *user_args = argp;

/* even if we caught a signal, we need to communicate success */
-		ret = 0;
+		ret = q->ownerdead ? -EOWNERDEAD : 0;

if (put_user(signaled, &user_args->index))
    		ret = -EFAULT;
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index a633db34f284..d7996180c1d2 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -43,5 +43,6 @@ struct ntsync_wait_args {

#define NTSYNC_IOC_SEM_POST		_IOWR('N', 0x81, __u32)
 #define NTSYNC_IOC_MUTEX_UNLOCK		_IOWR('N', 0x85, struct ntsync_mutex_args)
+#define NTSYNC_IOC_MUTEX_KILL		_IOW ('N', 0x86, __u32)

#endif

[PATCH v6 06/28] ntsync: Introduce NTSYNC_IOC_CREATE_EVENT.

[Elizabeth Figura]

This correspond to the NT syscall NtCreateEvent().

An NT event holds a single bit of state denoting whether it is signaled or
unsignaled.

There are two types of events: manual-reset and automatic-reset. When an
automatic-reset event is acquired via a wait function, its state is reset to
unsignaled. Manual-reset events are not affected by wait functions.

Whether the event is manual-reset, and its initial state, are specified at
creation time.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 62 +++++++++++++++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  7 +++++
 2 files changed, 69 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 0ed864d291a6..ef8949ee2d4b 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -26,6 +26,7 @@
 enum ntsync_type {
    NTSYNC_TYPE_SEM,
    NTSYNC_TYPE_MUTEX,
+	NTSYNC_TYPE_EVENT,
 };

/*
@@ -61,6 +62,10 @@ struct ntsync_obj {
    		pid_t owner;
    		bool ownerdead;
    	} mutex;
+		struct {
+			bool manual;
+			bool signaled;
+		} event;
    } u;

/*
@@ -233,6 +238,8 @@ static bool is_signaled(struct ntsync_obj *obj, __u32 owner)
    	if (obj->u.mutex.owner && obj->u.mutex.owner != owner)
    		return false;
    	return obj->u.mutex.count < UINT_MAX;
+	case NTSYNC_TYPE_EVENT:
+		return obj->u.event.signaled;
    }

WARN(1, "bad object type %#x\n", obj->type);
@@ -283,6 +290,10 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q,
    			obj->u.mutex.count++;
    			obj->u.mutex.owner = q->owner;
    			break;
+			case NTSYNC_TYPE_EVENT:
+				if (!obj->u.event.manual)
+					obj->u.event.signaled = false;
+				break;
    		}
    	}
    	wake_up_process(q->task);
@@ -353,6 +364,28 @@ static void try_wake_any_mutex(struct ntsync_obj *mutex)
    }
 }

+static void try_wake_any_event(struct ntsync_obj *event)
+{
+	struct ntsync_q_entry *entry;
+
+	ntsync_assert_held(event);
+	lockdep_assert(event->type == NTSYNC_TYPE_EVENT);
+
+	list_for_each_entry(entry, &event->any_waiters, node) {
+		struct ntsync_q *q = entry->q;
+		int signaled = -1;
+
+		if (!event->u.event.signaled)
+			break;
+
+		if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) {
+			if (!event->u.event.manual)
+				event->u.event.signaled = false;
+			wake_up_process(q->task);
+		}
+	}
+}
+
 /*
  * Actually change the semaphore state, returning -EOVERFLOW if it is made
  * invalid.
@@ -628,6 +661,30 @@ static int ntsync_create_mutex(struct ntsync_device *dev, void __user *argp)
    return put_user(fd, &user_args->mutex);
 }

+static int ntsync_create_event(struct ntsync_device *dev, void __user *argp)
+{
+	struct ntsync_event_args __user *user_args = argp;
+	struct ntsync_event_args args;
+	struct ntsync_obj *event;
+	int fd;
+
+	if (copy_from_user(&args, argp, sizeof(args)))
+		return -EFAULT;
+
+	event = ntsync_alloc_obj(dev, NTSYNC_TYPE_EVENT);
+	if (!event)
+		return -ENOMEM;
+	event->u.event.manual = args.manual;
+	event->u.event.signaled = args.signaled;
+	fd = ntsync_obj_get_fd(event);
+	if (fd < 0) {
+		kfree(event);
+		return fd;
+	}
+
+	return put_user(fd, &user_args->event);
+}
+
 static struct ntsync_obj *get_obj(struct ntsync_device *dev, int fd)
 {
    struct file *file = fget(fd);
@@ -758,6 +815,9 @@ static void try_wake_any_obj(struct ntsync_obj *obj)
    case NTSYNC_TYPE_MUTEX:
    	try_wake_any_mutex(obj);
    	break;
+	case NTSYNC_TYPE_EVENT:
+		try_wake_any_event(obj);
+		break;
    }
 }

@@ -947,6 +1007,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
    void __user *argp = (void __user *)parm;

switch (cmd) {
+	case NTSYNC_IOC_CREATE_EVENT:
+		return ntsync_create_event(dev, argp);
    case NTSYNC_IOC_CREATE_MUTEX:
    	return ntsync_create_mutex(dev, argp);
    case NTSYNC_IOC_CREATE_SEM:
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index d7996180c1d2..4c0c4271c7de 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -22,6 +22,12 @@ struct ntsync_mutex_args {
    __u32 count;
 };

+struct ntsync_event_args {
+	__u32 event;
+	__u32 manual;
+	__u32 signaled;
+};
+
 #define NTSYNC_WAIT_REALTIME	0x1

struct ntsync_wait_args {
@@ -40,6 +46,7 @@ struct ntsync_wait_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)
+#define NTSYNC_IOC_CREATE_EVENT		_IOWR('N', 0x87, struct ntsync_event_args)

#define NTSYNC_IOC_SEM_POST		_IOWR('N', 0x81, __u32)
 #define NTSYNC_IOC_MUTEX_UNLOCK		_IOWR('N', 0x85, struct ntsync_mutex_args)

[PATCH v6 07/28] ntsync: Introduce NTSYNC_IOC_EVENT_SET.

[Elizabeth Figura]

This corresponds to the NT syscall NtSetEvent().

This sets the event to the signaled state, and returns its previous state.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 27 +++++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 28 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index ef8949ee2d4b..e46dd795370a 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -534,6 +534,31 @@ static int ntsync_mutex_kill(struct ntsync_obj *mutex, void __user *argp)
    return ret;
 }

+static int ntsync_event_set(struct ntsync_obj *event, void __user *argp)
+{
+	struct ntsync_device *dev = event->dev;
+	__u32 prev_state;
+	bool all;
+
+	if (event->type != NTSYNC_TYPE_EVENT)
+		return -EINVAL;
+
+	all = ntsync_lock_obj(dev, event);
+
+	prev_state = event->u.event.signaled;
+	event->u.event.signaled = true;
+	if (all)
+		try_wake_all_obj(dev, event);
+	try_wake_any_event(event);
+
+	ntsync_unlock_obj(dev, event, all);
+
+	if (put_user(prev_state, (__u32 __user *)argp))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
    struct ntsync_obj *obj = file->private_data;
@@ -557,6 +582,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    	return ntsync_mutex_unlock(obj, argp);
    case NTSYNC_IOC_MUTEX_KILL:
    	return ntsync_mutex_kill(obj, argp);
+	case NTSYNC_IOC_EVENT_SET:
+		return ntsync_event_set(obj, argp);
    default:
    	return -ENOIOCTLCMD;
    }
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 4c0c4271c7de..36d903521bbe 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -51,5 +51,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_SEM_POST		_IOWR('N', 0x81, __u32)
 #define NTSYNC_IOC_MUTEX_UNLOCK		_IOWR('N', 0x85, struct ntsync_mutex_args)
 #define NTSYNC_IOC_MUTEX_KILL		_IOW ('N', 0x86, __u32)
+#define NTSYNC_IOC_EVENT_SET		_IOR ('N', 0x88, __u32)

#endif

[PATCH v6 08/28] ntsync: Introduce NTSYNC_IOC_EVENT_RESET.

[Elizabeth Figura]

This corresponds to the NT syscall NtResetEvent().

This sets the event to the unsignaled state, and returns its previous state.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 24 ++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 25 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index e46dd795370a..092133699193 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -559,6 +559,28 @@ static int ntsync_event_set(struct ntsync_obj *event, void __user *argp)
    return 0;
 }

+static int ntsync_event_reset(struct ntsync_obj *event, void __user *argp)
+{
+	struct ntsync_device *dev = event->dev;
+	__u32 prev_state;
+	bool all;
+
+	if (event->type != NTSYNC_TYPE_EVENT)
+		return -EINVAL;
+
+	all = ntsync_lock_obj(dev, event);
+
+	prev_state = event->u.event.signaled;
+	event->u.event.signaled = false;
+
+	ntsync_unlock_obj(dev, event, all);
+
+	if (put_user(prev_state, (__u32 __user *)argp))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
    struct ntsync_obj *obj = file->private_data;
@@ -584,6 +606,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    	return ntsync_mutex_kill(obj, argp);
    case NTSYNC_IOC_EVENT_SET:
    	return ntsync_event_set(obj, argp);
+	case NTSYNC_IOC_EVENT_RESET:
+		return ntsync_event_reset(obj, argp);
    default:
    	return -ENOIOCTLCMD;
    }
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 36d903521bbe..7fdf79729b20 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -52,5 +52,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_MUTEX_UNLOCK		_IOWR('N', 0x85, struct ntsync_mutex_args)
 #define NTSYNC_IOC_MUTEX_KILL		_IOW ('N', 0x86, __u32)
 #define NTSYNC_IOC_EVENT_SET		_IOR ('N', 0x88, __u32)
+#define NTSYNC_IOC_EVENT_RESET		_IOR ('N', 0x89, __u32)

#endif

[PATCH v6 09/28] ntsync: Introduce NTSYNC_IOC_EVENT_PULSE.

[Elizabeth Figura]

This corresponds to the NT syscall NtPulseEvent().

This wakes up any waiters as if the event had been set, but does not set the
event, instead resetting it if it had been signalled. Thus, for a manual-reset
event, all waiters are woken, whereas for an auto-reset event, at most one
waiter is woken.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 8 ++++++--
 include/uapi/linux/ntsync.h | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 092133699193..6b8352270874 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -534,7 +534,7 @@ static int ntsync_mutex_kill(struct ntsync_obj *mutex, void __user *argp)
    return ret;
 }

-static int ntsync_event_set(struct ntsync_obj *event, void __user *argp)
+static int ntsync_event_set(struct ntsync_obj *event, void __user *argp, bool pulse)
 {
    struct ntsync_device *dev = event->dev;
    __u32 prev_state;
@@ -550,6 +550,8 @@ static int ntsync_event_set(struct ntsync_obj *event, void __user *argp)
    if (all)
    	try_wake_all_obj(dev, event);
    try_wake_any_event(event);
+	if (pulse)
+		event->u.event.signaled = false;

ntsync_unlock_obj(dev, event, all);

@@ -605,9 +607,11 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    case NTSYNC_IOC_MUTEX_KILL:
    	return ntsync_mutex_kill(obj, argp);
    case NTSYNC_IOC_EVENT_SET:
-		return ntsync_event_set(obj, argp);
+		return ntsync_event_set(obj, argp, false);
    case NTSYNC_IOC_EVENT_RESET:
    	return ntsync_event_reset(obj, argp);
+	case NTSYNC_IOC_EVENT_PULSE:
+		return ntsync_event_set(obj, argp, true);
    default:
    	return -ENOIOCTLCMD;
    }
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 7fdf79729b20..5586fadd9bdd 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -53,5 +53,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_MUTEX_KILL		_IOW ('N', 0x86, __u32)
 #define NTSYNC_IOC_EVENT_SET		_IOR ('N', 0x88, __u32)
 #define NTSYNC_IOC_EVENT_RESET		_IOR ('N', 0x89, __u32)
+#define NTSYNC_IOC_EVENT_PULSE		_IOR ('N', 0x8a, __u32)

#endif

[PATCH v6 10/28] ntsync: Introduce NTSYNC_IOC_SEM_READ.

[Elizabeth Figura]

This corresponds to the NT syscall NtQuerySemaphore().

This returns the current count and maximum count of the semaphore.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 26 ++++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 27 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 6b8352270874..d6e8a4bde1d0 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -583,6 +583,30 @@ static int ntsync_event_reset(struct ntsync_obj *event, void __user *argp)
    return 0;
 }

+static int ntsync_sem_read(struct ntsync_obj *sem, void __user *argp)
+{
+	struct ntsync_sem_args __user *user_args = argp;
+	struct ntsync_device *dev = sem->dev;
+	struct ntsync_sem_args args;
+	bool all;
+
+	if (sem->type != NTSYNC_TYPE_SEM)
+		return -EINVAL;
+
+	args.sem = 0;
+
+	all = ntsync_lock_obj(dev, sem);
+
+	args.count = sem->u.sem.count;
+	args.max = sem->u.sem.max;
+
+	ntsync_unlock_obj(dev, sem, all);
+
+	if (copy_to_user(user_args, &args, sizeof(args)))
+		return -EFAULT;
+	return 0;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
    struct ntsync_obj *obj = file->private_data;
@@ -602,6 +626,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    switch (cmd) {
    case NTSYNC_IOC_SEM_POST:
    	return ntsync_sem_post(obj, argp);
+	case NTSYNC_IOC_SEM_READ:
+		return ntsync_sem_read(obj, argp);
    case NTSYNC_IOC_MUTEX_UNLOCK:
    	return ntsync_mutex_unlock(obj, argp);
    case NTSYNC_IOC_MUTEX_KILL:
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 5586fadd9bdd..5e922703686f 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -54,5 +54,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_EVENT_SET		_IOR ('N', 0x88, __u32)
 #define NTSYNC_IOC_EVENT_RESET		_IOR ('N', 0x89, __u32)
 #define NTSYNC_IOC_EVENT_PULSE		_IOR ('N', 0x8a, __u32)
+#define NTSYNC_IOC_SEM_READ		_IOR ('N', 0x8b, struct ntsync_sem_args)

#endif

[PATCH v6 11/28] ntsync: Introduce NTSYNC_IOC_MUTEX_READ.

[Elizabeth Figura]

This corresponds to the NT syscall NtQueryMutant().

This returns the recursion count, owner, and abandoned state of the mutex.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 28 ++++++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 29 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index d6e8a4bde1d0..cff2627c1efe 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -607,6 +607,32 @@ static int ntsync_sem_read(struct ntsync_obj *sem, void __user *argp)
    return 0;
 }

+static int ntsync_mutex_read(struct ntsync_obj *mutex, void __user *argp)
+{
+	struct ntsync_mutex_args __user *user_args = argp;
+	struct ntsync_device *dev = mutex->dev;
+	struct ntsync_mutex_args args;
+	bool all;
+	int ret;
+
+	if (mutex->type != NTSYNC_TYPE_MUTEX)
+		return -EINVAL;
+
+	args.mutex = 0;
+
+	all = ntsync_lock_obj(dev, mutex);
+
+	args.count = mutex->u.mutex.count;
+	args.owner = mutex->u.mutex.owner;
+	ret = mutex->u.mutex.ownerdead ? -EOWNERDEAD : 0;
+
+	ntsync_unlock_obj(dev, mutex, all);
+
+	if (copy_to_user(user_args, &args, sizeof(args)))
+		return -EFAULT;
+	return ret;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
    struct ntsync_obj *obj = file->private_data;
@@ -632,6 +658,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    	return ntsync_mutex_unlock(obj, argp);
    case NTSYNC_IOC_MUTEX_KILL:
    	return ntsync_mutex_kill(obj, argp);
+	case NTSYNC_IOC_MUTEX_READ:
+		return ntsync_mutex_read(obj, argp);
    case NTSYNC_IOC_EVENT_SET:
    	return ntsync_event_set(obj, argp, false);
    case NTSYNC_IOC_EVENT_RESET:
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 5e922703686f..eced73d08783 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -55,5 +55,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_EVENT_RESET		_IOR ('N', 0x89, __u32)
 #define NTSYNC_IOC_EVENT_PULSE		_IOR ('N', 0x8a, __u32)
 #define NTSYNC_IOC_SEM_READ		_IOR ('N', 0x8b, struct ntsync_sem_args)
+#define NTSYNC_IOC_MUTEX_READ		_IOR ('N', 0x8c, struct ntsync_mutex_args)

#endif

[PATCH v6 12/28] ntsync: Introduce NTSYNC_IOC_EVENT_READ.

[Elizabeth Figura]

This corresponds to the NT syscall NtQueryEvent().

This returns the signaled state of the event and whether it is manual-reset.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 26 ++++++++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 27 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index cff2627c1efe..5a5ee7b6ee92 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -633,6 +633,30 @@ static int ntsync_mutex_read(struct ntsync_obj *mutex, void __user *argp)
    return ret;
 }

+static int ntsync_event_read(struct ntsync_obj *event, void __user *argp)
+{
+	struct ntsync_event_args __user *user_args = argp;
+	struct ntsync_device *dev = event->dev;
+	struct ntsync_event_args args;
+	bool all;
+
+	if (event->type != NTSYNC_TYPE_EVENT)
+		return -EINVAL;
+
+	args.event = 0;
+
+	all = ntsync_lock_obj(dev, event);
+
+	args.manual = event->u.event.manual;
+	args.signaled = event->u.event.signaled;
+
+	ntsync_unlock_obj(dev, event, all);
+
+	if (copy_to_user(user_args, &args, sizeof(args)))
+		return -EFAULT;
+	return 0;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
    struct ntsync_obj *obj = file->private_data;
@@ -666,6 +690,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
    	return ntsync_event_reset(obj, argp);
    case NTSYNC_IOC_EVENT_PULSE:
    	return ntsync_event_set(obj, argp, true);
+	case NTSYNC_IOC_EVENT_READ:
+		return ntsync_event_read(obj, argp);
    default:
    	return -ENOIOCTLCMD;
    }
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index eced73d08783..74abeba832f7 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -56,5 +56,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_EVENT_PULSE		_IOR ('N', 0x8a, __u32)
 #define NTSYNC_IOC_SEM_READ		_IOR ('N', 0x8b, struct ntsync_sem_args)
 #define NTSYNC_IOC_MUTEX_READ		_IOR ('N', 0x8c, struct ntsync_mutex_args)
+#define NTSYNC_IOC_EVENT_READ		_IOR ('N', 0x8d, struct ntsync_event_args)

#endif

[PATCH v6 13/28] ntsync: Introduce alertable waits.

[Elizabeth Figura]

NT waits can optionally be made "alertable". This is a special channel for
thread wakeup that is mildly similar to SIGIO. A thread has an internal single
bit of "alerted" state, and if a thread is alerted while an alertable wait, the
wait will return a special value, consume the "alerted" state, and will not
consume any of its objects.

Alerts are implemented using events; the user-space NT emulator is expected to
create an internal ntsync event for each thread and pass that event to wait
functions.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/ntsync.c       | 70 ++++++++++++++++++++++++++++++++-----
 include/uapi/linux/ntsync.h |  3 +-
 2 files changed, 63 insertions(+), 10 deletions(-)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 5a5ee7b6ee92..3fac06270549 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -884,22 +884,29 @@ static int setup_wait(struct ntsync_device *dev,
    	      const struct ntsync_wait_args *args, bool all,
    	      struct ntsync_q **ret_q)
 {
+	int fds[NTSYNC_MAX_WAIT_COUNT + 1];
    const __u32 count = args->count;
-	int fds[NTSYNC_MAX_WAIT_COUNT];
    struct ntsync_q *q;
+	__u32 total_count;
    __u32 i, j;

-	if (args->pad[0] || args->pad[1] || (args->flags & ~NTSYNC_WAIT_REALTIME))
+	if (args->pad || (args->flags & ~NTSYNC_WAIT_REALTIME))
    	return -EINVAL;

if (args->count > NTSYNC_MAX_WAIT_COUNT)
    	return -EINVAL;

+	total_count = count;
+	if (args->alert)
+		total_count++;
+
    if (copy_from_user(fds, u64_to_user_ptr(args->objs),
    		   array_size(count, sizeof(*fds))))
    	return -EFAULT;
+	if (args->alert)
+		fds[count] = args->alert;

-	q = kmalloc(struct_size(q, entries, count), GFP_KERNEL);
+	q = kmalloc(struct_size(q, entries, total_count), GFP_KERNEL);
    if (!q)
    	return -ENOMEM;
    q->task = current;
@@ -909,7 +916,7 @@ static int setup_wait(struct ntsync_device *dev,
    q->ownerdead = false;
    q->count = count;

-	for (i = 0; i < count; i++) {
+	for (i = 0; i < total_count; i++) {
    	struct ntsync_q_entry *entry = &q->entries[i];
    	struct ntsync_obj *obj = get_obj(dev, fds[i]);

@@ -959,10 +966,10 @@ static void try_wake_any_obj(struct ntsync_obj *obj)
 static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
 {
    struct ntsync_wait_args args;
+	__u32 i, total_count;
    struct ntsync_q *q;
    int signaled;
    bool all;
-	__u32 i;
    int ret;

if (copy_from_user(&args, argp, sizeof(args)))
@@ -972,9 +979,13 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    if (ret < 0)
    	return ret;

+	total_count = args.count;
+	if (args.alert)
+		total_count++;
+
    /* queue ourselves */

-	for (i = 0; i < args.count; i++) {
+	for (i = 0; i < total_count; i++) {
    	struct ntsync_q_entry *entry = &q->entries[i];
    	struct ntsync_obj *obj = entry->obj;

@@ -983,9 +994,15 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)
    	ntsync_unlock_obj(dev, obj, all);
    }

-	/* check if we are already signaled */
+	/*
+	 * Check if we are already signaled.
+	 *
+	 * Note that the API requires that normal objects are checked before
+	 * the alert event. Hence we queue the alert event last, and check
+	 * objects in order.
+	 */

-	for (i = 0; i < args.count; i++) {
+	for (i = 0; i < total_count; i++) {
    	struct ntsync_obj *obj = q->entries[i].obj;

if (atomic_read(&q->signaled) != -1)
@@ -1002,7 +1019,7 @@ static int ntsync_wait_any(struct ntsync_device *dev, void __user *argp)

/* and finally, unqueue */

-	for (i = 0; i < args.count; i++) {
+	for (i = 0; i < total_count; i++) {
    	struct ntsync_q_entry *entry = &q->entries[i];
    	struct ntsync_obj *obj = entry->obj;

@@ -1062,6 +1079,14 @@ static int ntsync_wait_all(struct ntsync_device *dev, void __user *argp)
    	 */
    	list_add_tail(&entry->node, &obj->all_waiters);
    }
+	if (args.alert) {
+		struct ntsync_q_entry *entry = &q->entries[args.count];
+		struct ntsync_obj *obj = entry->obj;
+
+		dev_lock_obj(dev, obj);
+		list_add_tail(&entry->node, &obj->any_waiters);
+		dev_unlock_obj(dev, obj);
+	}

/* check if we are already signaled */

@@ -1069,6 +1094,21 @@ static int ntsync_wait_all(struct ntsync_device *dev, void __user *argp)

mutex_unlock(&dev->wait_all_lock);

+	/*
+	 * Check if the alert event is signaled, making sure to do so only
+	 * after checking if the other objects are signaled.
+	 */
+
+	if (args.alert) {
+		struct ntsync_obj *obj = q->entries[args.count].obj;
+
+		if (atomic_read(&q->signaled) == -1) {
+			bool all = ntsync_lock_obj(dev, obj);
+			try_wake_any_obj(obj);
+			ntsync_unlock_obj(dev, obj, all);
+		}
+	}
+
    /* sleep */

ret = ntsync_schedule(q, &args);
@@ -1094,6 +1134,18 @@ static int ntsync_wait_all(struct ntsync_device *dev, void __user *argp)

mutex_unlock(&dev->wait_all_lock);

+	if (args.alert) {
+		struct ntsync_q_entry *entry = &q->entries[args.count];
+		struct ntsync_obj *obj = entry->obj;
+		bool all;
+
+		all = ntsync_lock_obj(dev, obj);
+		list_del(&entry->node);
+		ntsync_unlock_obj(dev, obj, all);
+
+		put_obj(obj);
+	}
+
    signaled = atomic_read(&q->signaled);
    if (signaled != -1) {
    	struct ntsync_wait_args __user *user_args = argp;
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 74abeba832f7..4a8095a3fc34 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -37,7 +37,8 @@ struct ntsync_wait_args {
    __u32 index;
    __u32 flags;
    __u32 owner;
-	__u32 pad[2];
+	__u32 alert;
+	__u32 pad;
 };

#define NTSYNC_MAX_WAIT_COUNT 64

[PATCH v6 14/28] selftests: ntsync: Add some tests for semaphore state.

[Elizabeth Figura]

Wine has tests for its synchronization primitives, but these are more accessible
to kernel developers, and also allow us to test some edge cases that Wine does
not care about.

This patch adds tests for semaphore-specific ioctls NTSYNC_IOC_SEM_POST and
NTSYNC_IOC_SEM_READ, and waiting on semaphores.

Signed-off-by: Elizabeth Figura 
---
 tools/testing/selftests/Makefile              |   1 +
 .../selftests/drivers/ntsync/.gitignore       |   1 +
 .../testing/selftests/drivers/ntsync/Makefile |   7 +
 tools/testing/selftests/drivers/ntsync/config |   1 +
 .../testing/selftests/drivers/ntsync/ntsync.c | 149 ++++++++++++++++++
 5 files changed, 159 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/ntsync/.gitignore
 create mode 100644 tools/testing/selftests/drivers/ntsync/Makefile
 create mode 100644 tools/testing/selftests/drivers/ntsync/config
 create mode 100644 tools/testing/selftests/drivers/ntsync/ntsync.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 2401e973c359..a8c9648e5adc 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -18,6 +18,7 @@ TARGETS += devices/error_logs
 TARGETS += devices/probe
 TARGETS += dmabuf-heaps
 TARGETS += drivers/dma-buf
+TARGETS += drivers/ntsync
 TARGETS += drivers/s390x/uvdevice
 TARGETS += drivers/net
 TARGETS += drivers/net/bonding
diff --git a/tools/testing/selftests/drivers/ntsync/.gitignore b/tools/testing/selftests/drivers/ntsync/.gitignore
new file mode 100644
index 000000000000..848573a3d3ea
--- /dev/null
+++ b/tools/testing/selftests/drivers/ntsync/.gitignore
@@ -0,0 +1 @@
+ntsync
diff --git a/tools/testing/selftests/drivers/ntsync/Makefile b/tools/testing/selftests/drivers/ntsync/Makefile
new file mode 100644
index 000000000000..dbf2b055c0b2
--- /dev/null
+++ b/tools/testing/selftests/drivers/ntsync/Makefile
@@ -0,0 +1,7 @@
+# SPDX-LICENSE-IDENTIFIER: GPL-2.0-only
+TEST_GEN_PROGS := ntsync
+
+CFLAGS += $(KHDR_INCLUDES)
+LDLIBS += -lpthread
+
+include ../../lib.mk
diff --git a/tools/testing/selftests/drivers/ntsync/config b/tools/testing/selftests/drivers/ntsync/config
new file mode 100644
index 000000000000..60539c826d06
--- /dev/null
+++ b/tools/testing/selftests/drivers/ntsync/config
@@ -0,0 +1 @@
+CONFIG_WINESYNC=y
diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
new file mode 100644
index 000000000000..1e145c6dfded
--- /dev/null
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Various unit tests for the "ntsync" synchronization primitive driver.
+ *
+ * Copyright (C) 2021-2022 Elizabeth Figura 
+ */
+
+#define _GNU_SOURCE
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <time.h>
+#include <pthread.h>
+#include <linux/ntsync.h>
+#include "../../kselftest_harness.h"
+
+static int read_sem_state(int sem, __u32 *count, __u32 *max)
+{
+	struct ntsync_sem_args args;
+	int ret;
+
+	memset(&args, 0xcc, sizeof(args));
+	ret = ioctl(sem, NTSYNC_IOC_SEM_READ, &args);
+	*count = args.count;
+	*max = args.max;
+	return ret;
+}
+
+#define check_sem_state(sem, count, max) \
+	({ \
+		__u32 __count, __max; \
+		int ret = read_sem_state((sem), &__count, &__max); \
+		EXPECT_EQ(0, ret); \
+		EXPECT_EQ((count), __count); \
+		EXPECT_EQ((max), __max); \
+	})
+
+static int post_sem(int sem, __u32 *count)
+{
+	return ioctl(sem, NTSYNC_IOC_SEM_POST, count);
+}
+
+static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index)
+{
+	struct ntsync_wait_args args = {0};
+	struct timespec timeout;
+	int ret;
+
+	clock_gettime(CLOCK_MONOTONIC, &timeout);
+
+	args.timeout = timeout.tv_sec * 1000000000 + timeout.tv_nsec;
+	args.count = count;
+	args.objs = (uintptr_t)objs;
+	args.owner = owner;
+	args.index = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_WAIT_ANY, &args);
+	*index = args.index;
+	return ret;
+}
+
+TEST(semaphore_state)
+{
+	struct ntsync_sem_args sem_args;
+	struct timespec timeout;
+	__u32 count, index;
+	int fd, ret, sem;
+
+	clock_gettime(CLOCK_MONOTONIC, &timeout);
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	sem_args.count = 3;
+	sem_args.max = 2;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	sem_args.count = 2;
+	sem_args.max = 2;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+	sem = sem_args.sem;
+	check_sem_state(sem, 2, 2);
+
+	count = 0;
+	ret = post_sem(sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, count);
+	check_sem_state(sem, 2, 2);
+
+	count = 1;
+	ret = post_sem(sem, &count);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOVERFLOW, errno);
+	check_sem_state(sem, 2, 2);
+
+	ret = wait_any(fd, 1, &sem, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem, 1, 2);
+
+	ret = wait_any(fd, 1, &sem, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem, 0, 2);
+
+	ret = wait_any(fd, 1, &sem, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	count = 3;
+	ret = post_sem(sem, &count);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOVERFLOW, errno);
+	check_sem_state(sem, 0, 2);
+
+	count = 2;
+	ret = post_sem(sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+	check_sem_state(sem, 2, 2);
+
+	ret = wait_any(fd, 1, &sem, 123, &index);
+	EXPECT_EQ(0, ret);
+	ret = wait_any(fd, 1, &sem, 123, &index);
+	EXPECT_EQ(0, ret);
+
+	count = 1;
+	ret = post_sem(sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+	check_sem_state(sem, 1, 2);
+
+	count = ~0u;
+	ret = post_sem(sem, &count);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOVERFLOW, errno);
+	check_sem_state(sem, 1, 2);
+
+	close(sem);
+
+	close(fd);
+}
+
+TEST_HARNESS_MAIN

[PATCH v6 15/28] selftests: ntsync: Add some tests for mutex state.

[Elizabeth Figura]

Test mutex-specific ioctls NTSYNC_IOC_MUTEX_UNLOCK and NTSYNC_IOC_MUTEX_READ,
and waiting on mutexes.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 196 ++++++++++++++++++
 1 file changed, 196 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 1e145c6dfded..7cd0f40594fd 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -40,6 +40,39 @@ static int post_sem(int sem, __u32 *count)
    return ioctl(sem, NTSYNC_IOC_SEM_POST, count);
 }

+static int read_mutex_state(int mutex, __u32 *count, __u32 *owner)
+{
+	struct ntsync_mutex_args args;
+	int ret;
+
+	memset(&args, 0xcc, sizeof(args));
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &args);
+	*count = args.count;
+	*owner = args.owner;
+	return ret;
+}
+
+#define check_mutex_state(mutex, count, owner) \
+	({ \
+		__u32 __count, __owner; \
+		int ret = read_mutex_state((mutex), &__count, &__owner); \
+		EXPECT_EQ(0, ret); \
+		EXPECT_EQ((count), __count); \
+		EXPECT_EQ((owner), __owner); \
+	})
+
+static int unlock_mutex(int mutex, __u32 owner, __u32 *count)
+{
+	struct ntsync_mutex_args args;
+	int ret;
+
+	args.owner = owner;
+	args.count = 0xdeadbeef;
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_UNLOCK, &args);
+	*count = args.count;
+	return ret;
+}
+
 static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index)
 {
    struct ntsync_wait_args args = {0};
@@ -146,4 +179,167 @@ TEST(semaphore_state)
    close(fd);
 }

+TEST(mutex_state)
+{
+	struct ntsync_mutex_args mutex_args;
+	__u32 owner, count, index;
+	struct timespec timeout;
+	int fd, ret, mutex;
+
+	clock_gettime(CLOCK_MONOTONIC, &timeout);
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	mutex_args.owner = 123;
+	mutex_args.count = 0;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	mutex_args.owner = 0;
+	mutex_args.count = 2;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	mutex_args.owner = 123;
+	mutex_args.count = 2;
+	mutex_args.mutex = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, mutex_args.mutex);
+	mutex = mutex_args.mutex;
+	check_mutex_state(mutex, 2, 123);
+
+	ret = unlock_mutex(mutex, 0, &count);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	ret = unlock_mutex(mutex, 456, &count);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EPERM, errno);
+	check_mutex_state(mutex, 2, 123);
+
+	ret = unlock_mutex(mutex, 123, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, count);
+	check_mutex_state(mutex, 1, 123);
+
+	ret = unlock_mutex(mutex, 123, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, count);
+	check_mutex_state(mutex, 0, 0);
+
+	ret = unlock_mutex(mutex, 123, &count);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EPERM, errno);
+
+	ret = wait_any(fd, 1, &mutex, 456, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_mutex_state(mutex, 1, 456);
+
+	ret = wait_any(fd, 1, &mutex, 456, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_mutex_state(mutex, 2, 456);
+
+	ret = unlock_mutex(mutex, 456, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, count);
+	check_mutex_state(mutex, 1, 456);
+
+	ret = wait_any(fd, 1, &mutex, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	owner = 0;
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	owner = 123;
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EPERM, errno);
+	check_mutex_state(mutex, 1, 456);
+
+	owner = 456;
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner);
+	EXPECT_EQ(0, ret);
+
+	memset(&mutex_args, 0xcc, sizeof(mutex_args));
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &mutex_args);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOWNERDEAD, errno);
+	EXPECT_EQ(0, mutex_args.count);
+	EXPECT_EQ(0, mutex_args.owner);
+
+	memset(&mutex_args, 0xcc, sizeof(mutex_args));
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &mutex_args);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOWNERDEAD, errno);
+	EXPECT_EQ(0, mutex_args.count);
+	EXPECT_EQ(0, mutex_args.owner);
+
+	ret = wait_any(fd, 1, &mutex, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOWNERDEAD, errno);
+	EXPECT_EQ(0, index);
+	check_mutex_state(mutex, 1, 123);
+
+	owner = 123;
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner);
+	EXPECT_EQ(0, ret);
+
+	memset(&mutex_args, 0xcc, sizeof(mutex_args));
+	ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &mutex_args);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOWNERDEAD, errno);
+	EXPECT_EQ(0, mutex_args.count);
+	EXPECT_EQ(0, mutex_args.owner);
+
+	ret = wait_any(fd, 1, &mutex, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOWNERDEAD, errno);
+	EXPECT_EQ(0, index);
+	check_mutex_state(mutex, 1, 123);
+
+	close(mutex);
+
+	mutex_args.owner = 0;
+	mutex_args.count = 0;
+	mutex_args.mutex = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, mutex_args.mutex);
+	mutex = mutex_args.mutex;
+	check_mutex_state(mutex, 0, 0);
+
+	ret = wait_any(fd, 1, &mutex, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_mutex_state(mutex, 1, 123);
+
+	close(mutex);
+
+	mutex_args.owner = 123;
+	mutex_args.count = ~0u;
+	mutex_args.mutex = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, mutex_args.mutex);
+	mutex = mutex_args.mutex;
+	check_mutex_state(mutex, ~0u, 123);
+
+	ret = wait_any(fd, 1, &mutex, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	close(mutex);
+
+	close(fd);
+}
+
 TEST_HARNESS_MAIN

[PATCH v6 16/28] selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ANY.

[Elizabeth Figura]

Test basic synchronous functionality of NTSYNC_IOC_WAIT_ANY, when objects are
considered signaled or not signaled, and how they are affected by a successful
wait.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 119 ++++++++++++++++++
 1 file changed, 119 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 7cd0f40594fd..40ad8cbd3138 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -342,4 +342,123 @@ TEST(mutex_state)
    close(fd);
 }

+TEST(test_wait_any)
+{
+	int objs[NTSYNC_MAX_WAIT_COUNT + 1], fd, ret;
+	struct ntsync_mutex_args mutex_args = {0};
+	struct ntsync_sem_args sem_args = {0};
+	__u32 owner, index, count, i;
+	struct timespec timeout;
+
+	clock_gettime(CLOCK_MONOTONIC, &timeout);
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	sem_args.count = 2;
+	sem_args.max = 3;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+
+	mutex_args.owner = 0;
+	mutex_args.count = 0;
+	mutex_args.mutex = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, mutex_args.mutex);
+
+	objs[0] = sem_args.sem;
+	objs[1] = mutex_args.mutex;
+
+	ret = wait_any(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 1, 3);
+	check_mutex_state(mutex_args.mutex, 0, 0);
+
+	ret = wait_any(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 0, 3);
+	check_mutex_state(mutex_args.mutex, 0, 0);
+
+	ret = wait_any(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, index);
+	check_sem_state(sem_args.sem, 0, 3);
+	check_mutex_state(mutex_args.mutex, 1, 123);
+
+	count = 1;
+	ret = post_sem(sem_args.sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+
+	ret = wait_any(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 0, 3);
+	check_mutex_state(mutex_args.mutex, 1, 123);
+
+	ret = wait_any(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, index);
+	check_sem_state(sem_args.sem, 0, 3);
+	check_mutex_state(mutex_args.mutex, 2, 123);
+
+	ret = wait_any(fd, 2, objs, 456, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	owner = 123;
+	ret = ioctl(mutex_args.mutex, NTSYNC_IOC_MUTEX_KILL, &owner);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_any(fd, 2, objs, 456, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOWNERDEAD, errno);
+	EXPECT_EQ(1, index);
+
+	ret = wait_any(fd, 2, objs, 456, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, index);
+
+	/* test waiting on the same object twice */
+	count = 2;
+	ret = post_sem(sem_args.sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+
+	objs[0] = objs[1] = sem_args.sem;
+	ret = wait_any(fd, 2, objs, 456, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 1, 3);
+
+	ret = wait_any(fd, 0, NULL, 456, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	for (i = 0; i < NTSYNC_MAX_WAIT_COUNT + 1; ++i)
+		objs[i] = sem_args.sem;
+
+	ret = wait_any(fd, NTSYNC_MAX_WAIT_COUNT, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+
+	ret = wait_any(fd, NTSYNC_MAX_WAIT_COUNT + 1, objs, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	ret = wait_any(fd, -1, objs, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	close(sem_args.sem);
+	close(mutex_args.mutex);
+
+	close(fd);
+}
+
 TEST_HARNESS_MAIN

[PATCH v6 17/28] selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ALL.

[Elizabeth Figura]

Test basic synchronous functionality of NTSYNC_IOC_WAIT_ALL, and when objects
are considered simultaneously signaled.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 99 ++++++++++++++++++-
 1 file changed, 97 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 40ad8cbd3138..c0f372167557 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -73,7 +73,8 @@ static int unlock_mutex(int mutex, __u32 owner, __u32 *count)
    return ret;
 }

-static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index)
+static int wait_objs(int fd, unsigned long request, __u32 count,
+		     const int *objs, __u32 owner, __u32 *index)
 {
    struct ntsync_wait_args args = {0};
    struct timespec timeout;
@@ -86,11 +87,21 @@ static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *in
    args.objs = (uintptr_t)objs;
    args.owner = owner;
    args.index = 0xdeadbeef;
-	ret = ioctl(fd, NTSYNC_IOC_WAIT_ANY, &args);
+	ret = ioctl(fd, request, &args);
    *index = args.index;
    return ret;
 }

+static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index)
+{
+	return wait_objs(fd, NTSYNC_IOC_WAIT_ANY, count, objs, owner, index);
+}
+
+static int wait_all(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index)
+{
+	return wait_objs(fd, NTSYNC_IOC_WAIT_ALL, count, objs, owner, index);
+}
+
 TEST(semaphore_state)
 {
    struct ntsync_sem_args sem_args;
@@ -461,4 +472,88 @@ TEST(test_wait_any)
    close(fd);
 }

+TEST(test_wait_all)
+{
+	struct ntsync_mutex_args mutex_args = {0};
+	struct ntsync_sem_args sem_args = {0};
+	__u32 owner, index, count;
+	int objs[2], fd, ret;
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	sem_args.count = 2;
+	sem_args.max = 3;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+
+	mutex_args.owner = 0;
+	mutex_args.count = 0;
+	mutex_args.mutex = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, mutex_args.mutex);
+
+	objs[0] = sem_args.sem;
+	objs[1] = mutex_args.mutex;
+
+	ret = wait_all(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 1, 3);
+	check_mutex_state(mutex_args.mutex, 1, 123);
+
+	ret = wait_all(fd, 2, objs, 456, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+	check_sem_state(sem_args.sem, 1, 3);
+	check_mutex_state(mutex_args.mutex, 1, 123);
+
+	ret = wait_all(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 0, 3);
+	check_mutex_state(mutex_args.mutex, 2, 123);
+
+	ret = wait_all(fd, 2, objs, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+	check_sem_state(sem_args.sem, 0, 3);
+	check_mutex_state(mutex_args.mutex, 2, 123);
+
+	count = 3;
+	ret = post_sem(sem_args.sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+
+	ret = wait_all(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 2, 3);
+	check_mutex_state(mutex_args.mutex, 3, 123);
+
+	owner = 123;
+	ret = ioctl(mutex_args.mutex, NTSYNC_IOC_MUTEX_KILL, &owner);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_all(fd, 2, objs, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EOWNERDEAD, errno);
+	check_sem_state(sem_args.sem, 1, 3);
+	check_mutex_state(mutex_args.mutex, 1, 123);
+
+	/* test waiting on the same object twice */
+	objs[0] = objs[1] = sem_args.sem;
+	ret = wait_all(fd, 2, objs, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(EINVAL, errno);
+
+	close(sem_args.sem);
+	close(mutex_args.mutex);
+
+	close(fd);
+}
+
 TEST_HARNESS_MAIN

[PATCH v6 18/28] selftests: ntsync: Add some tests for wakeup signaling with WINESYNC_IOC_WAIT_ANY.

[Elizabeth Figura]

Test contended "wait-for-any" waits, to make sure that scheduling and wakeup
logic works correctly.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 150 ++++++++++++++++++
 1 file changed, 150 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index c0f372167557..993f5db23768 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -556,4 +556,154 @@ TEST(test_wait_all)
    close(fd);
 }

+struct wake_args {
+	int fd;
+	int obj;
+};
+
+struct wait_args {
+	int fd;
+	unsigned long request;
+	struct ntsync_wait_args *args;
+	int ret;
+	int err;
+};
+
+static void *wait_thread(void *arg)
+{
+	struct wait_args *args = arg;
+
+	args->ret = ioctl(args->fd, args->request, args->args);
+	args->err = errno;
+	return NULL;
+}
+
+static __u64 get_abs_timeout(unsigned int ms)
+{
+	struct timespec timeout;
+	clock_gettime(CLOCK_MONOTONIC, &timeout);
+	return (timeout.tv_sec * 1000000000) + timeout.tv_nsec + (ms * 1000000);
+}
+
+static int wait_for_thread(pthread_t thread, unsigned int ms)
+{
+	struct timespec timeout;
+
+	clock_gettime(CLOCK_REALTIME, &timeout);
+	timeout.tv_nsec += ms * 1000000;
+	timeout.tv_sec += (timeout.tv_nsec / 1000000000);
+	timeout.tv_nsec %= 1000000000;
+	return pthread_timedjoin_np(thread, NULL, &timeout);
+}
+
+TEST(wake_any)
+{
+	struct ntsync_mutex_args mutex_args = {0};
+	struct ntsync_wait_args wait_args = {0};
+	struct ntsync_sem_args sem_args = {0};
+	struct wait_args thread_args;
+	int objs[2], fd, ret;
+	__u32 count, index;
+	pthread_t thread;
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	sem_args.count = 0;
+	sem_args.max = 3;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+
+	mutex_args.owner = 123;
+	mutex_args.count = 1;
+	mutex_args.mutex = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, mutex_args.mutex);
+
+	objs[0] = sem_args.sem;
+	objs[1] = mutex_args.mutex;
+
+	/* test waking the semaphore */
+
+	wait_args.timeout = get_abs_timeout(1000);
+	wait_args.objs = (uintptr_t)objs;
+	wait_args.count = 2;
+	wait_args.owner = 456;
+	wait_args.index = 0xdeadbeef;
+	thread_args.fd = fd;
+	thread_args.args = &wait_args;
+	thread_args.request = NTSYNC_IOC_WAIT_ANY;
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	count = 1;
+	ret = post_sem(sem_args.sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+	check_sem_state(sem_args.sem, 0, 3);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(0, wait_args.index);
+
+	/* test waking the mutex */
+
+	/* first grab it again for owner 123 */
+	ret = wait_any(fd, 1, &mutex_args.mutex, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+
+	wait_args.timeout = get_abs_timeout(1000);
+	wait_args.owner = 456;
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	ret = unlock_mutex(mutex_args.mutex, 123, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, count);
+
+	ret = pthread_tryjoin_np(thread, NULL);
+	EXPECT_EQ(EBUSY, ret);
+
+	ret = unlock_mutex(mutex_args.mutex, 123, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, mutex_args.count);
+	check_mutex_state(mutex_args.mutex, 1, 456);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(1, wait_args.index);
+
+	/* delete an object while it's being waited on */
+
+	wait_args.timeout = get_abs_timeout(200);
+	wait_args.owner = 123;
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	close(sem_args.sem);
+	close(mutex_args.mutex);
+
+	ret = wait_for_thread(thread, 200);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(-1, thread_args.ret);
+	EXPECT_EQ(ETIMEDOUT, thread_args.err);
+
+	close(fd);
+}
+
 TEST_HARNESS_MAIN

[PATCH v6 19/28] selftests: ntsync: Add some tests for wakeup signaling with WINESYNC_IOC_WAIT_ALL.

[Elizabeth Figura]

Test contended "wait-for-all" waits, to make sure that scheduling and wakeup
logic works correctly, and that the wait only exits once objects are all
simultaneously signaled.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 98 +++++++++++++++++++
 1 file changed, 98 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 993f5db23768..b77fb0b2c4b1 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -706,4 +706,102 @@ TEST(wake_any)
    close(fd);
 }

+TEST(wake_all)
+{
+	struct ntsync_mutex_args mutex_args = {0};
+	struct ntsync_wait_args wait_args = {0};
+	struct ntsync_sem_args sem_args = {0};
+	struct wait_args thread_args;
+	int objs[2], fd, ret;
+	__u32 count, index;
+	pthread_t thread;
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	sem_args.count = 0;
+	sem_args.max = 3;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+
+	mutex_args.owner = 123;
+	mutex_args.count = 1;
+	mutex_args.mutex = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, mutex_args.mutex);
+
+	objs[0] = sem_args.sem;
+	objs[1] = mutex_args.mutex;
+
+	wait_args.timeout = get_abs_timeout(1000);
+	wait_args.objs = (uintptr_t)objs;
+	wait_args.count = 2;
+	wait_args.owner = 456;
+	thread_args.fd = fd;
+	thread_args.args = &wait_args;
+	thread_args.request = NTSYNC_IOC_WAIT_ALL;
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	count = 1;
+	ret = post_sem(sem_args.sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+
+	ret = pthread_tryjoin_np(thread, NULL);
+	EXPECT_EQ(EBUSY, ret);
+
+	check_sem_state(sem_args.sem, 1, 3);
+
+	ret = wait_any(fd, 1, &sem_args.sem, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+
+	ret = unlock_mutex(mutex_args.mutex, 123, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, count);
+
+	ret = pthread_tryjoin_np(thread, NULL);
+	EXPECT_EQ(EBUSY, ret);
+
+	check_mutex_state(mutex_args.mutex, 0, 0);
+
+	count = 2;
+	ret = post_sem(sem_args.sem, &count);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, count);
+	check_sem_state(sem_args.sem, 1, 3);
+	check_mutex_state(mutex_args.mutex, 1, 456);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+
+	/* delete an object while it's being waited on */
+
+	wait_args.timeout = get_abs_timeout(200);
+	wait_args.owner = 123;
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	close(sem_args.sem);
+	close(mutex_args.mutex);
+
+	ret = wait_for_thread(thread, 200);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(-1, thread_args.ret);
+	EXPECT_EQ(ETIMEDOUT, thread_args.err);
+
+	close(fd);
+}
+
 TEST_HARNESS_MAIN

[PATCH v6 20/28] selftests: ntsync: Add some tests for manual-reset event state.

[Elizabeth Figura]

Test event-specific ioctls NTSYNC_IOC_EVENT_SET, NTSYNC_IOC_EVENT_RESET,
NTSYNC_IOC_EVENT_PULSE, NTSYNC_IOC_EVENT_READ for manual-reset events, and
waiting on manual-reset events.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 89 +++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index b77fb0b2c4b1..b6481c2b85cc 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -73,6 +73,27 @@ static int unlock_mutex(int mutex, __u32 owner, __u32 *count)
    return ret;
 }

+static int read_event_state(int event, __u32 *signaled, __u32 *manual)
+{
+	struct ntsync_event_args args;
+	int ret;
+
+	memset(&args, 0xcc, sizeof(args));
+	ret = ioctl(event, NTSYNC_IOC_EVENT_READ, &args);
+	*signaled = args.signaled;
+	*manual = args.manual;
+	return ret;
+}
+
+#define check_event_state(event, signaled, manual) \
+	({ \
+		__u32 __signaled, __manual; \
+		int ret = read_event_state((event), &__signaled, &__manual); \
+		EXPECT_EQ(0, ret); \
+		EXPECT_EQ((signaled), __signaled); \
+		EXPECT_EQ((manual), __manual); \
+	})
+
 static int wait_objs(int fd, unsigned long request, __u32 count,
    	     const int *objs, __u32 owner, __u32 *index)
 {
@@ -353,6 +374,74 @@ TEST(mutex_state)
    close(fd);
 }

+TEST(manual_event_state)
+{
+	struct ntsync_event_args event_args;
+	__u32 index, signaled;
+	int fd, event, ret;
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	event_args.manual = 1;
+	event_args.signaled = 0;
+	event_args.event = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, event_args.event);
+	event = event_args.event;
+	check_event_state(event, 0, 1);
+
+	signaled = 0xdeadbeef;
+	ret = ioctl(event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event, 1, 1);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+	check_event_state(event, 1, 1);
+
+	ret = wait_any(fd, 1, &event, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_event_state(event, 1, 1);
+
+	signaled = 0xdeadbeef;
+	ret = ioctl(event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+	check_event_state(event, 0, 1);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event, 0, 1);
+
+	ret = wait_any(fd, 1, &event, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_PULSE, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+	check_event_state(event, 0, 1);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_PULSE, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event, 0, 1);
+
+	close(event);
+
+	close(fd);
+}
+
 TEST(test_wait_any)
 {
    int objs[NTSYNC_MAX_WAIT_COUNT + 1], fd, ret;

[PATCH v6 21/28] selftests: ntsync: Add some tests for auto-reset event state.

[Elizabeth Figura]

Test event-specific ioctls NTSYNC_IOC_EVENT_SET, NTSYNC_IOC_EVENT_RESET,
NTSYNC_IOC_EVENT_PULSE, NTSYNC_IOC_EVENT_READ for auto-reset events, and
waiting on auto-reset events.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 59 +++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index b6481c2b85cc..12ccb4ec28e4 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -442,6 +442,65 @@ TEST(manual_event_state)
    close(fd);
 }

+TEST(auto_event_state)
+{
+	struct ntsync_event_args event_args;
+	__u32 index, signaled;
+	int fd, event, ret;
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	event_args.manual = 0;
+	event_args.signaled = 1;
+	event_args.event = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, event_args.event);
+	event = event_args.event;
+
+	check_event_state(event, 1, 0);
+
+	signaled = 0xdeadbeef;
+	ret = ioctl(event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+	check_event_state(event, 1, 0);
+
+	ret = wait_any(fd, 1, &event, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_event_state(event, 0, 0);
+
+	signaled = 0xdeadbeef;
+	ret = ioctl(event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event, 0, 0);
+
+	ret = wait_any(fd, 1, &event, 123, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_PULSE, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+	check_event_state(event, 0, 0);
+
+	ret = ioctl(event, NTSYNC_IOC_EVENT_PULSE, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event, 0, 0);
+
+	close(event);
+
+	close(fd);
+}
+
 TEST(test_wait_any)
 {
    int objs[NTSYNC_MAX_WAIT_COUNT + 1], fd, ret;

[PATCH v6 22/28] selftests: ntsync: Add some tests for wakeup signaling with events.

[Elizabeth Figura]

Expand the contended wait tests, which previously only covered events and
semaphores, to cover events as well.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 151 +++++++++++++++++-
 1 file changed, 147 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 12ccb4ec28e4..5d17eff6a370 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -622,6 +622,7 @@ TEST(test_wait_any)

TEST(test_wait_all)
 {
+	struct ntsync_event_args event_args = {0};
    struct ntsync_mutex_args mutex_args = {0};
    struct ntsync_sem_args sem_args = {0};
    __u32 owner, index, count;
@@ -644,6 +645,11 @@ TEST(test_wait_all)
    EXPECT_EQ(0, ret);
    EXPECT_NE(0xdeadbeef, mutex_args.mutex);

+	event_args.manual = true;
+	event_args.signaled = true;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+
    objs[0] = sem_args.sem;
    objs[1] = mutex_args.mutex;

@@ -692,6 +698,14 @@ TEST(test_wait_all)
    check_sem_state(sem_args.sem, 1, 3);
    check_mutex_state(mutex_args.mutex, 1, 123);

+	objs[0] = sem_args.sem;
+	objs[1] = event_args.event;
+	ret = wait_all(fd, 2, objs, 123, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+	check_sem_state(sem_args.sem, 0, 3);
+	check_event_state(event_args.event, 1, 1);
+
    /* test waiting on the same object twice */
    objs[0] = objs[1] = sem_args.sem;
    ret = wait_all(fd, 2, objs, 123, &index);
@@ -700,6 +714,7 @@ TEST(test_wait_all)

close(sem_args.sem);
    close(mutex_args.mutex);
+	close(event_args.event);

close(fd);
 }
@@ -746,12 +761,13 @@ static int wait_for_thread(pthread_t thread, unsigned int ms)

TEST(wake_any)
 {
+	struct ntsync_event_args event_args = {0};
    struct ntsync_mutex_args mutex_args = {0};
    struct ntsync_wait_args wait_args = {0};
    struct ntsync_sem_args sem_args = {0};
    struct wait_args thread_args;
+	__u32 count, index, signaled;
    int objs[2], fd, ret;
-	__u32 count, index;
    pthread_t thread;

fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
@@ -833,10 +849,101 @@ TEST(wake_any)
    EXPECT_EQ(0, thread_args.ret);
    EXPECT_EQ(1, wait_args.index);

+	/* test waking events */
+
+	event_args.manual = false;
+	event_args.signaled = false;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+
+	objs[1] = event_args.event;
+	wait_args.timeout = get_abs_timeout(1000);
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event_args.event, 0, 0);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(1, wait_args.index);
+
+	wait_args.timeout = get_abs_timeout(1000);
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_PULSE, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event_args.event, 0, 0);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(1, wait_args.index);
+
+	close(event_args.event);
+
+	event_args.manual = true;
+	event_args.signaled = false;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+
+	objs[1] = event_args.event;
+	wait_args.timeout = get_abs_timeout(1000);
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event_args.event, 1, 1);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(1, wait_args.index);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+
+	wait_args.timeout = get_abs_timeout(1000);
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_PULSE, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+	check_event_state(event_args.event, 0, 1);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(1, wait_args.index);
+
+	close(event_args.event);
+
    /* delete an object while it's being waited on */

wait_args.timeout = get_abs_timeout(200);
    wait_args.owner = 123;
+	objs[1] = mutex_args.mutex;
    ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
    EXPECT_EQ(0, ret);

@@ -856,12 +963,14 @@ TEST(wake_any)

TEST(wake_all)
 {
+	struct ntsync_event_args manual_event_args = {0};
+	struct ntsync_event_args auto_event_args = {0};
    struct ntsync_mutex_args mutex_args = {0};
    struct ntsync_wait_args wait_args = {0};
    struct ntsync_sem_args sem_args = {0};
    struct wait_args thread_args;
-	int objs[2], fd, ret;
-	__u32 count, index;
+	__u32 count, index, signaled;
+	int objs[4], fd, ret;
    pthread_t thread;

fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
@@ -881,12 +990,24 @@ TEST(wake_all)
    EXPECT_EQ(0, ret);
    EXPECT_NE(0xdeadbeef, mutex_args.mutex);

+	manual_event_args.manual = true;
+	manual_event_args.signaled = true;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &manual_event_args);
+	EXPECT_EQ(0, ret);
+
+	auto_event_args.manual = false;
+	auto_event_args.signaled = true;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &auto_event_args);
+	EXPECT_EQ(0, ret);
+
    objs[0] = sem_args.sem;
    objs[1] = mutex_args.mutex;
+	objs[2] = manual_event_args.event;
+	objs[3] = auto_event_args.event;

wait_args.timeout = get_abs_timeout(1000);
    wait_args.objs = (uintptr_t)objs;
-	wait_args.count = 2;
+	wait_args.count = 4;
    wait_args.owner = 456;
    thread_args.fd = fd;
    thread_args.args = &wait_args;
@@ -920,12 +1041,32 @@ TEST(wake_all)

check_mutex_state(mutex_args.mutex, 0, 0);

+	ret = ioctl(manual_event_args.event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+
    count = 2;
    ret = post_sem(sem_args.sem, &count);
    EXPECT_EQ(0, ret);
    EXPECT_EQ(0, count);
+	check_sem_state(sem_args.sem, 2, 3);
+
+	ret = ioctl(auto_event_args.event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, signaled);
+
+	ret = ioctl(manual_event_args.event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+
+	ret = ioctl(auto_event_args.event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, signaled);
+
    check_sem_state(sem_args.sem, 1, 3);
    check_mutex_state(mutex_args.mutex, 1, 456);
+	check_event_state(manual_event_args.event, 1, 1);
+	check_event_state(auto_event_args.event, 0, 0);

ret = wait_for_thread(thread, 100);
    EXPECT_EQ(0, ret);
@@ -943,6 +1084,8 @@ TEST(wake_all)

close(sem_args.sem);
    close(mutex_args.mutex);
+	close(manual_event_args.event);
+	close(auto_event_args.event);

ret = wait_for_thread(thread, 200);
    EXPECT_EQ(0, ret);

[PATCH v6 23/28] selftests: ntsync: Add tests for alertable waits.

[Elizabeth Figura]

Test the "alert" functionality of NTSYNC_IOC_WAIT_ALL and NTSYNC_IOC_WAIT_ANY,
when a wait is woken with an alert and when it is woken by an object.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 179 +++++++++++++++++-
 1 file changed, 176 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 5d17eff6a370..5465a16d38b3 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -95,7 +95,7 @@ static int read_event_state(int event, __u32 *signaled, __u32 *manual)
    })

static int wait_objs(int fd, unsigned long request, __u32 count,
-		     const int *objs, __u32 owner, __u32 *index)
+		     const int *objs, __u32 owner, int alert, __u32 *index)
 {
    struct ntsync_wait_args args = {0};
    struct timespec timeout;
@@ -108,6 +108,7 @@ static int wait_objs(int fd, unsigned long request, __u32 count,
    args.objs = (uintptr_t)objs;
    args.owner = owner;
    args.index = 0xdeadbeef;
+	args.alert = alert;
    ret = ioctl(fd, request, &args);
    *index = args.index;
    return ret;
@@ -115,12 +116,26 @@ static int wait_objs(int fd, unsigned long request, __u32 count,

static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index)
 {
-	return wait_objs(fd, NTSYNC_IOC_WAIT_ANY, count, objs, owner, index);
+	return wait_objs(fd, NTSYNC_IOC_WAIT_ANY, count, objs, owner, 0, index);
 }

static int wait_all(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index)
 {
-	return wait_objs(fd, NTSYNC_IOC_WAIT_ALL, count, objs, owner, index);
+	return wait_objs(fd, NTSYNC_IOC_WAIT_ALL, count, objs, owner, 0, index);
+}
+
+static int wait_any_alert(int fd, __u32 count, const int *objs,
+			  __u32 owner, int alert, __u32 *index)
+{
+	return wait_objs(fd, NTSYNC_IOC_WAIT_ANY,
+			 count, objs, owner, alert, index);
+}
+
+static int wait_all_alert(int fd, __u32 count, const int *objs,
+			  __u32 owner, int alert, __u32 *index)
+{
+	return wait_objs(fd, NTSYNC_IOC_WAIT_ALL,
+			 count, objs, owner, alert, index);
 }

TEST(semaphore_state)
@@ -1095,4 +1110,162 @@ TEST(wake_all)
    close(fd);
 }

+TEST(alert_any)
+{
+	struct ntsync_event_args event_args = {0};
+	struct ntsync_sem_args sem_args = {0};
+	__u32 index, count, signaled;
+	int objs[2], fd, ret;
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	sem_args.count = 0;
+	sem_args.max = 2;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+	objs[0] = sem_args.sem;
+
+	sem_args.count = 1;
+	sem_args.max = 2;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+	objs[1] = sem_args.sem;
+
+	event_args.manual = true;
+	event_args.signaled = true;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_any_alert(fd, 0, NULL, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_any_alert(fd, 0, NULL, 123, event_args.event, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(1, index);
+
+	ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, index);
+
+	close(event_args.event);
+
+	/* test with an auto-reset event */
+
+	event_args.manual = false;
+	event_args.signaled = true;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+
+	count = 1;
+	ret = post_sem(objs[0], &count);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+
+	ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, index);
+
+	ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	close(event_args.event);
+
+	close(objs[0]);
+	close(objs[1]);
+
+	close(fd);
+}
+
+TEST(alert_all)
+{
+	struct ntsync_event_args event_args = {0};
+	struct ntsync_sem_args sem_args = {0};
+	__u32 index, count, signaled;
+	int objs[2], fd, ret;
+
+	fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, fd);
+
+	sem_args.count = 2;
+	sem_args.max = 2;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+	objs[0] = sem_args.sem;
+
+	sem_args.count = 1;
+	sem_args.max = 2;
+	sem_args.sem = 0xdeadbeef;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args);
+	EXPECT_EQ(0, ret);
+	EXPECT_NE(0xdeadbeef, sem_args.sem);
+	objs[1] = sem_args.sem;
+
+	event_args.manual = true;
+	event_args.signaled = true;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+
+	ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, index);
+
+	close(event_args.event);
+
+	/* test with an auto-reset event */
+
+	event_args.manual = false;
+	event_args.signaled = true;
+	ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+
+	count = 2;
+	ret = post_sem(objs[1], &count);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, index);
+
+	ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(2, index);
+
+	ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index);
+	EXPECT_EQ(-1, ret);
+	EXPECT_EQ(ETIMEDOUT, errno);
+
+	close(event_args.event);
+
+	close(objs[0]);
+	close(objs[1]);
+
+	close(fd);
+}
+
 TEST_HARNESS_MAIN

[PATCH v6 24/28] selftests: ntsync: Add some tests for wakeup signaling via alerts.

[Elizabeth Figura]

Expand the alert tests to cover alerting a thread mid-wait, to test that the
relevant scheduling logic works correctly.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 5465a16d38b3..968874d7e325 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -1113,9 +1113,12 @@ TEST(wake_all)
 TEST(alert_any)
 {
    struct ntsync_event_args event_args = {0};
+	struct ntsync_wait_args wait_args = {0};
    struct ntsync_sem_args sem_args = {0};
    __u32 index, count, signaled;
+	struct wait_args thread_args;
    int objs[2], fd, ret;
+	pthread_t thread;

fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
    ASSERT_LE(0, fd);
@@ -1163,6 +1166,34 @@ TEST(alert_any)
    EXPECT_EQ(0, ret);
    EXPECT_EQ(2, index);

+	/* test wakeup via alert */
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+
+	wait_args.timeout = get_abs_timeout(1000);
+	wait_args.objs = (uintptr_t)objs;
+	wait_args.count = 2;
+	wait_args.owner = 123;
+	wait_args.index = 0xdeadbeef;
+	wait_args.alert = event_args.event;
+	thread_args.fd = fd;
+	thread_args.args = &wait_args;
+	thread_args.request = NTSYNC_IOC_WAIT_ANY;
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(2, wait_args.index);
+
    close(event_args.event);

/* test with an auto-reset event */
@@ -1199,9 +1230,12 @@ TEST(alert_any)
 TEST(alert_all)
 {
    struct ntsync_event_args event_args = {0};
+	struct ntsync_wait_args wait_args = {0};
    struct ntsync_sem_args sem_args = {0};
+	struct wait_args thread_args;
    __u32 index, count, signaled;
    int objs[2], fd, ret;
+	pthread_t thread;

fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
    ASSERT_LE(0, fd);
@@ -1235,6 +1269,34 @@ TEST(alert_all)
    EXPECT_EQ(0, ret);
    EXPECT_EQ(2, index);

+	/* test wakeup via alert */
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_RESET, &signaled);
+	EXPECT_EQ(0, ret);
+
+	wait_args.timeout = get_abs_timeout(1000);
+	wait_args.objs = (uintptr_t)objs;
+	wait_args.count = 2;
+	wait_args.owner = 123;
+	wait_args.index = 0xdeadbeef;
+	wait_args.alert = event_args.event;
+	thread_args.fd = fd;
+	thread_args.args = &wait_args;
+	thread_args.request = NTSYNC_IOC_WAIT_ALL;
+	ret = pthread_create(&thread, NULL, wait_thread, &thread_args);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(ETIMEDOUT, ret);
+
+	ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+
+	ret = wait_for_thread(thread, 100);
+	EXPECT_EQ(0, ret);
+	EXPECT_EQ(0, thread_args.ret);
+	EXPECT_EQ(2, wait_args.index);
+
    close(event_args.event);

/* test with an auto-reset event */

[PATCH v6 25/28] selftests: ntsync: Add a stress test for contended waits.

[Elizabeth Figura]

Test a more realistic usage pattern, and one with heavy contention, in order to
actually exercise ntsync's internal synchronization.

This test has several threads in a tight loop acquiring a mutex, modifying some
shared data, and then releasing the mutex. At the end we check if the data is
consistent.

Signed-off-by: Elizabeth Figura 
---
 .../testing/selftests/drivers/ntsync/ntsync.c | 74 +++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 968874d7e325..5fa2c9a0768c 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -1330,4 +1330,78 @@ TEST(alert_all)
    close(fd);
 }

+#define STRESS_LOOPS 10000
+#define STRESS_THREADS 4
+
+static unsigned int stress_counter;
+static int stress_device, stress_start_event, stress_mutex;
+
+static void *stress_thread(void *arg)
+{
+	struct ntsync_wait_args wait_args = {0};
+	__u32 index, count, i;
+	int ret;
+
+	wait_args.timeout = UINT64_MAX;
+	wait_args.count = 1;
+	wait_args.objs = (uintptr_t)&stress_start_event;
+	wait_args.owner = gettid();
+	wait_args.index = 0xdeadbeef;
+
+	ioctl(stress_device, NTSYNC_IOC_WAIT_ANY, &wait_args);
+
+	wait_args.objs = (uintptr_t)&stress_mutex;
+
+	for (i = 0; i < STRESS_LOOPS; ++i) {
+		ioctl(stress_device, NTSYNC_IOC_WAIT_ANY, &wait_args);
+
+		++stress_counter;
+
+		unlock_mutex(stress_mutex, wait_args.owner, &count);
+	}
+
+	return NULL;
+}
+
+TEST(stress_wait)
+{
+	struct ntsync_event_args event_args;
+	struct ntsync_mutex_args mutex_args;
+	pthread_t threads[STRESS_THREADS];
+	__u32 signaled, i;
+	int ret;
+
+	stress_device = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);
+	ASSERT_LE(0, stress_device);
+
+	mutex_args.owner = 0;
+	mutex_args.count = 0;
+	ret = ioctl(stress_device, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+	EXPECT_EQ(0, ret);
+	stress_mutex = mutex_args.mutex;
+
+	event_args.manual = 1;
+	event_args.signaled = 0;
+	ret = ioctl(stress_device, NTSYNC_IOC_CREATE_EVENT, &event_args);
+	EXPECT_EQ(0, ret);
+	stress_start_event = event_args.event;
+
+	for (i = 0; i < STRESS_THREADS; ++i)
+		pthread_create(&threads[i], NULL, stress_thread, NULL);
+
+	ret = ioctl(stress_start_event, NTSYNC_IOC_EVENT_SET, &signaled);
+	EXPECT_EQ(0, ret);
+
+	for (i = 0; i < STRESS_THREADS; ++i) {
+		ret = pthread_join(threads[i], NULL);
+		EXPECT_EQ(0, ret);
+	}
+
+	EXPECT_EQ(STRESS_LOOPS * STRESS_THREADS, stress_counter);
+
+	close(stress_start_event);
+	close(stress_mutex);
+	close(stress_device);
+}
+
 TEST_HARNESS_MAIN

[PATCH v6 26/28] maintainers: Add an entry for ntsync.

[Elizabeth Figura]

Add myself as maintainer, supported by CodeWeavers.

Signed-off-by: Elizabeth Figura 
---
 MAINTAINERS | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 1e930c7a58b1..8c3dd9077fc2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16708,6 +16708,15 @@ T:	git https://github.com/Paragon-Software-Group/linux-ntfs3.git
 F:	Documentation/filesystems/ntfs3.rst
 F:	fs/ntfs3/

+NTSYNC SYNCHRONIZATION PRIMITIVE DRIVER
+M:	Elizabeth Figura 
+L:	[e-mail]
+S:	Supported
+F:	Documentation/userspace-api/ntsync.rst
+F:	drivers/misc/ntsync.c
+F:	include/uapi/linux/ntsync.h
+F:	tools/testing/selftests/drivers/ntsync/
+
 NUBUS SUBSYSTEM
 M:	Finn Thain 
 L:	[e-mail]

[PATCH v6 27/28] docs: ntsync: Add documentation for the ntsync uAPI.

[Elizabeth Figura]

Add an overall explanation of the driver architecture, and complete and precise
specification for its intended behaviour.

Signed-off-by: Elizabeth Figura 
---
 Documentation/userspace-api/index.rst  |   1 +
 Documentation/userspace-api/ntsync.rst | 398 +++++++++++++++++++++++++
 2 files changed, 399 insertions(+)
 create mode 100644 Documentation/userspace-api/ntsync.rst

diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst
index 274cc7546efc..9c1b15cd89ab 100644
--- a/Documentation/userspace-api/index.rst
+++ b/Documentation/userspace-api/index.rst
@@ -63,6 +63,7 @@ Everything else
    vduse
    futex2
    perf_ring_buffer
+   ntsync

.. only::  subproject and html

diff --git a/Documentation/userspace-api/ntsync.rst b/Documentation/userspace-api/ntsync.rst
new file mode 100644
index 000000000000..767844637a7d
--- /dev/null
+++ b/Documentation/userspace-api/ntsync.rst
@@ -0,0 +1,398 @@
+===================================
+NT synchronization primitive driver
+===================================
+
+This page documents the user-space API for the ntsync driver.
+
+ntsync is a support driver for emulation of NT synchronization
+primitives by user-space NT emulators. It exists because implementation
+in user-space, using existing tools, cannot match Windows performance
+while offering accurate semantics. It is implemented entirely in
+software, and does not drive any hardware device.
+
+This interface is meant as a compatibility tool only, and should not
+be used for general synchronization. Instead use generic, versatile
+interfaces such as futex(2) and poll(2).
+
+Synchronization primitives
+==========================
+
+The ntsync driver exposes three types of synchronization primitives:
+semaphores, mutexes, and events.
+
+A semaphore holds a single volatile 32-bit counter, and a static 32-bit
+integer denoting the maximum value. It is considered signaled (that is,
+can be acquired without contention, or will wake up a waiting thread)
+when the counter is nonzero. The counter is decremented by one when a
+wait is satisfied. Both the initial and maximum count are established
+when the semaphore is created.
+
+A mutex holds a volatile 32-bit recursion count, and a volatile 32-bit
+identifier denoting its owner. A mutex is considered signaled when its
+owner is zero (indicating that it is not owned). The recursion count is
+incremented when a wait is satisfied, and ownership is set to the given
+identifier.
+
+A mutex also holds an internal flag denoting whether its previous owner
+has died; such a mutex is said to be abandoned. Owner death is not
+tracked automatically based on thread death, but rather must be
+communicated using ``NTSYNC_IOC_MUTEX_KILL``. An abandoned mutex is
+inherently considered unowned.
+
+Except for the "unowned" semantics of zero, the actual value of the
+owner identifier is not interpreted by the ntsync driver at all. The
+intended use is to store a thread identifier; however, the ntsync
+driver does not actually validate that a calling thread provides
+consistent or unique identifiers.
+
+An event is similar to a semaphore with a maximum count of one. It holds
+a volatile boolean state denoting whether it is signaled or not. There
+are two types of events, auto-reset and manual-reset. An auto-reset
+event is designaled when a wait is satisfied; a manual-reset event is
+not. The event type is specified when the event is created.
+
+Unless specified otherwise, all operations on an object are atomic and
+totally ordered with respect to other operations on the same object.
+
+Objects are represented by files. When all file descriptors to an
+object are closed, that object is deleted.
+
+Char device
+===========
+
+The ntsync driver creates a single char device /dev/ntsync. Each file
+description opened on the device represents a unique instance intended
+to back an individual NT virtual machine. Objects created by one ntsync
+instance may only be used with other objects created by the same
+instance.
+
+ioctl reference
+===============
+
+All operations on the device are done through ioctls. There are four
+structures used in ioctl calls::
+
+   struct ntsync_sem_args {
+   	__u32 sem;
+   	__u32 count;
+   	__u32 max;
+   };
+
+   struct ntsync_mutex_args {
+   	__u32 mutex;
+   	__u32 owner;
+   	__u32 count;
+   };
+
+   struct ntsync_event_args {
+   	__u32 event;
+   	__u32 signaled;
+   	__u32 manual;
+   };
+
+   struct ntsync_wait_args {
+   	__u64 timeout;
+   	__u64 objs;
+   	__u32 count;
+   	__u32 owner;
+   	__u32 index;
+   	__u32 alert;
+   	__u32 flags;
+   	__u32 pad;
+   };
+
+Depending on the ioctl, members of the structure may be used as input,
+output, or not at all. All ioctls return 0 on success.
+
+The ioctls on the device file are as follows:
+
+.. c:macro:: NTSYNC_IOC_CREATE_SEM
+
+  Create a semaphore object. Takes a pointer to struct
+  :c:type:`ntsync_sem_args`, which is used as follows:
+
+  .. list-table::
+
+     * - ``sem``
+       - On output, contains a file descriptor to the created semaphore.
+     * - ``count``
+       - Initial count of the semaphore.
+     * - ``max``
+       - Maximum count of the semaphore.
+
+  Fails with ``EINVAL`` if ``count`` is greater than ``max``.
+
+.. c:macro:: NTSYNC_IOC_CREATE_MUTEX
+
+  Create a mutex object. Takes a pointer to struct
+  :c:type:`ntsync_mutex_args`, which is used as follows:
+
+  .. list-table::
+
+     * - ``mutex``
+       - On output, contains a file descriptor to the created mutex.
+     * - ``count``
+       - Initial recursion count of the mutex.
+     * - ``owner``
+       - Initial owner of the mutex.
+
+  If ``owner`` is nonzero and ``count`` is zero, or if ``owner`` is
+  zero and ``count`` is nonzero, the function fails with ``EINVAL``.
+
+.. c:macro:: NTSYNC_IOC_CREATE_EVENT
+
+  Create an event object. Takes a pointer to struct
+  :c:type:`ntsync_event_args`, which is used as follows:
+
+  .. list-table::
+
+     * - ``event``
+       - On output, contains a file descriptor to the created event.
+     * - ``signaled``
+       - If nonzero, the event is initially signaled, otherwise
+         nonsignaled.
+     * - ``manual``
+       - If nonzero, the event is a manual-reset event, otherwise
+         auto-reset.
+
+The ioctls on the individual objects are as follows:
+
+.. c:macro:: NTSYNC_IOC_SEM_POST
+
+  Post to a semaphore object. Takes a pointer to a 32-bit integer,
+  which on input holds the count to be added to the semaphore, and on
+  output contains its previous count.
+
+  If adding to the semaphore's current count would raise the latter
+  past the semaphore's maximum count, the ioctl fails with
+  ``EOVERFLOW`` and the semaphore is not affected. If raising the
+  semaphore's count causes it to become signaled, eligible threads
+  waiting on this semaphore will be woken and the semaphore's count
+  decremented appropriately.
+
+.. c:macro:: NTSYNC_IOC_MUTEX_UNLOCK
+
+  Release a mutex object. Takes a pointer to struct
+  :c:type:`ntsync_mutex_args`, which is used as follows:
+
+  .. list-table::
+
+     * - ``mutex``
+       - Ignored.
+     * - ``owner``
+       - Specifies the owner trying to release this mutex.
+     * - ``count``
+       - On output, contains the previous recursion count.
+
+  If ``owner`` is zero, the ioctl fails with ``EINVAL``. If ``owner``
+  is not the current owner of the mutex, the ioctl fails with
+  ``EPERM``.
+
+  The mutex's count will be decremented by one. If decrementing the
+  mutex's count causes it to become zero, the mutex is marked as
+  unowned and signaled, and eligible threads waiting on it will be
+  woken as appropriate.
+
+.. c:macro:: NTSYNC_IOC_SET_EVENT
+
+  Signal an event object. Takes a pointer to a 32-bit integer, which on
+  output contains the previous state of the event.
+
+  Eligible threads will be woken, and auto-reset events will be
+  designaled appropriately.
+
+.. c:macro:: NTSYNC_IOC_RESET_EVENT
+
+  Designal an event object. Takes a pointer to a 32-bit integer, which
+  on output contains the previous state of the event.
+
+.. c:macro:: NTSYNC_IOC_PULSE_EVENT
+
+  Wake threads waiting on an event object while leaving it in an
+  unsignaled state. Takes a pointer to a 32-bit integer, which on
+  output contains the previous state of the event.
+
+  A pulse operation can be thought of as a set followed by a reset,
+  performed as a single atomic operation. If two threads are waiting on
+  an auto-reset event which is pulsed, only one will be woken. If two
+  threads are waiting a manual-reset event which is pulsed, both will
+  be woken. However, in both cases, the event will be unsignaled
+  afterwards, and a simultaneous read operation will always report the
+  event as unsignaled.
+
+.. c:macro:: NTSYNC_IOC_READ_SEM
+
+  Read the current state of a semaphore object. Takes a pointer to
+  struct :c:type:`ntsync_sem_args`, which is used as follows:
+
+  .. list-table::
+
+     * - ``sem``
+       - Ignored.
+     * - ``count``
+       - On output, contains the current count of the semaphore.
+     * - ``max``
+       - On output, contains the maximum count of the semaphore.
+
+.. c:macro:: NTSYNC_IOC_READ_MUTEX
+
+  Read the current state of a mutex object. Takes a pointer to struct
+  :c:type:`ntsync_mutex_args`, which is used as follows:
+
+  .. list-table::
+
+     * - ``mutex``
+       - Ignored.
+     * - ``owner``
+       - On output, contains the current owner of the mutex, or zero
+         if the mutex is not currently owned.
+     * - ``count``
+       - On output, contains the current recursion count of the mutex.
+
+  If the mutex is marked as abandoned, the function fails with
+  ``EOWNERDEAD``. In this case, ``count`` and ``owner`` are set to
+  zero.
+
+.. c:macro:: NTSYNC_IOC_READ_EVENT
+
+  Read the current state of an event object. Takes a pointer to struct
+  :c:type:`ntsync_event_args`, which is used as follows:
+
+  .. list-table::
+
+     * - ``event``
+       - Ignored.
+     * - ``signaled``
+       - On output, contains the current state of the event.
+     * - ``manual``
+       - On output, contains 1 if the event is a manual-reset event,
+         and 0 otherwise.
+
+.. c:macro:: NTSYNC_IOC_KILL_OWNER
+
+  Mark a mutex as unowned and abandoned if it is owned by the given
+  owner. Takes an input-only pointer to a 32-bit integer denoting the
+  owner. If the owner is zero, the ioctl fails with ``EINVAL``. If the
+  owner does not own the mutex, the function fails with ``EPERM``.
+
+  Eligible threads waiting on the mutex will be woken as appropriate
+  (and such waits will fail with ``EOWNERDEAD``, as described below).
+
+.. c:macro:: NTSYNC_IOC_WAIT_ANY
+
+  Poll on any of a list of objects, atomically acquiring at most one.
+  Takes a pointer to struct :c:type:`ntsync_wait_args`, which is
+  used as follows:
+
+  .. list-table::
+
+     * - ``timeout``
+       - Absolute timeout in nanoseconds. If ``NTSYNC_WAIT_REALTIME``
+         is set, the timeout is measured against the REALTIME clock;
+         otherwise it is measured against the MONOTONIC clock. If the
+         timeout is equal to or earlier than the current time, the
+         function returns immediately without sleeping. If ``timeout``
+         is U64_MAX, the function will sleep until an object is
+         signaled, and will not fail with ``ETIMEDOUT``.
+     * - ``objs``
+       - Pointer to an array of ``count`` file descriptors
+         (specified as an integer so that the structure has the same
+         size regardless of architecture). If any object is
+         invalid, the function fails with ``EINVAL``.
+     * - ``count``
+       - Number of objects specified in the ``objs`` array.
+         If greater than ``NTSYNC_MAX_WAIT_COUNT``, the function fails
+         with ``EINVAL``.
+     * - ``owner``
+       - Mutex owner identifier. If any object in ``objs`` is a mutex,
+         the ioctl will attempt to acquire that mutex on behalf of
+         ``owner``. If ``owner`` is zero, the ioctl fails with
+         ``EINVAL``.
+     * - ``index``
+       - On success, contains the index (into ``objs``) of the object
+         which was signaled. If ``alert`` was signaled instead,
+         this contains ``count``.
+     * - ``alert``
+       - Optional event object file descriptor. If nonzero, this
+         specifies an "alert" event object which, if signaled, will
+         terminate the wait. If nonzero, the identifier must point to a
+         valid event.
+     * - ``flags``
+       - Zero or more flags. Currently the only flag is
+         ``NTSYNC_WAIT_REALTIME``, which causes the timeout to be
+         measured against the REALTIME clock instead of MONOTONIC.
+     * - ``pad``
+       - Unused, must be set to zero.
+
+  This function attempts to acquire one of the given objects. If unable
+  to do so, it sleeps until an object becomes signaled, subsequently
+  acquiring it, or the timeout expires. In the latter case the ioctl
+  fails with ``ETIMEDOUT``. The function only acquires one object, even
+  if multiple objects are signaled.
+
+  A semaphore is considered to be signaled if its count is nonzero, and
+  is acquired by decrementing its count by one. A mutex is considered
+  to be signaled if it is unowned or if its owner matches the ``owner``
+  argument, and is acquired by incrementing its recursion count by one
+  and setting its owner to the ``owner`` argument. An auto-reset event
+  is acquired by designaling it; a manual-reset event is not affected
+  by acquisition.
+
+  Acquisition is atomic and totally ordered with respect to other
+  operations on the same object. If two wait operations (with different
+  ``owner`` identifiers) are queued on the same mutex, only one is
+  signaled. If two wait operations are queued on the same semaphore,
+  and a value of one is posted to it, only one is signaled.
+
+  If an abandoned mutex is acquired, the ioctl fails with
+  ``EOWNERDEAD``. Although this is a failure return, the function may
+  otherwise be considered successful. The mutex is marked as owned by
+  the given owner (with a recursion count of 1) and as no longer
+  abandoned, and ``index`` is still set to the index of the mutex.
+
+  The ``alert`` argument is an "extra" event which can terminate the
+  wait, independently of all other objects.
+
+  It is valid to pass the same object more than once, including by
+  passing the same event in the ``objs`` array and in ``alert``. If a
+  wakeup occurs due to that object being signaled, ``index`` is set to
+  the lowest index corresponding to that object.
+
+  The function may fail with ``EINTR`` if a signal is received.
+
+.. c:macro:: NTSYNC_IOC_WAIT_ALL
+
+  Poll on a list of objects, atomically acquiring all of them. Takes a
+  pointer to struct :c:type:`ntsync_wait_args`, which is used
+  identically to ``NTSYNC_IOC_WAIT_ANY``, except that ``index`` is
+  always filled with zero on success if not woken via alert.
+
+  This function attempts to simultaneously acquire all of the given
+  objects. If unable to do so, it sleeps until all objects become
+  simultaneously signaled, subsequently acquiring them, or the timeout
+  expires. In the latter case the ioctl fails with ``ETIMEDOUT`` and no
+  objects are modified.
+
+  Objects may become signaled and subsequently designaled (through
+  acquisition by other threads) while this thread is sleeping. Only
+  once all objects are simultaneously signaled does the ioctl acquire
+  them and return. The entire acquisition is atomic and totally ordered
+  with respect to other operations on any of the given objects.
+
+  If an abandoned mutex is acquired, the ioctl fails with
+  ``EOWNERDEAD``. Similarly to ``NTSYNC_IOC_WAIT_ANY``, all objects are
+  nevertheless marked as acquired. Note that if multiple mutex objects
+  are specified, there is no way to know which were marked as
+  abandoned.
+
+  As with "any" waits, the ``alert`` argument is an "extra" event which
+  can terminate the wait. Critically, however, an "all" wait will
+  succeed if all members in ``objs`` are signaled, *or* if ``alert`` is
+  signaled. In the latter case ``index`` will be set to ``count``. As
+  with "any" waits, if both conditions are filled, the former takes
+  priority, and objects in ``objs`` will be acquired.
+
+  Unlike ``NTSYNC_IOC_WAIT_ANY``, it is not valid to pass the same
+  object more than once, nor is it valid to pass the same object in
+  ``objs`` and in ``alert``. If this is attempted, the function fails
+  with ``EINVAL``.

[PATCH v6 28/28] ntsync: No longer depend on BROKEN.

[Elizabeth Figura]

f5b335dc025cfee90957efa90dc72fada0d5abb4 ("misc: ntsync: mark driver as "broken"
to prevent from building") was committed to avoid the driver being used while
only part of its functionality was released. Since the rest of the functionality
has now been committed, revert this.

Signed-off-by: Elizabeth Figura 
---
 drivers/misc/Kconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 09cbe3f0ab1e..fb772bfe27c3 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -517,7 +517,6 @@ config OPEN_DICE

config NTSYNC
    tristate "NT synchronization primitive emulation"
-	depends on BROKEN
    help
      This module provides kernel support for emulation of Windows NT
      synchronization primitives. It is not a hardware driver.