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 <zfigura@xxxxxxxxxxxxxxx>
---
drivers/misc/ntsync.c | 60 +++++++++++++++++++++++++++++++++++++
include/uapi/linux/ntsync.h | 7 +++++
2 files changed, 67 insertions(+)
diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index a3466be50c45..17dd47d06e0a 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -25,6 +25,7 @@
enum ntsync_type {
NTSYNC_TYPE_SEM,
NTSYNC_TYPE_MUTEX,
+ NTSYNC_TYPE_EVENT,
};
/*
@@ -59,6 +60,10 @@ struct ntsync_obj {
__u32 owner;
bool ownerdead;
} mutex;
+ struct {
+ bool manual;
+ bool signaled;
+ } event;
} u;
/*
@@ -143,6 +148,8 @@ 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);
@@ -192,6 +199,10 @@ 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);
@@ -258,6 +269,26 @@ 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;
+
+ lockdep_assert_held(&event->lock);
+
+ list_for_each_entry(entry, &event->any_waiters, node) {
+ struct ntsync_q *q = entry->q;
+
+ if (!event->u.event.signaled)
+ break;
+
+ if (atomic_cmpxchg(&q->signaled, -1, entry->index) == -1) {
+ 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.
@@ -566,6 +597,30 @@ 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);
@@ -689,6 +744,9 @@ 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;
}
}
@@ -877,6 +935,8 @@ 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 4800941fcbda..040cbdb39033 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;
+};
+
struct ntsync_wait_args {
__u64 timeout;
__u64 objs;
@@ -37,6 +43,7 @@ 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)
--
2.43.0
