1 /******************************************************************************
4 * Driver for receiving and demuxing event-channel signals.
6 * Copyright (c) 2004-2005, K A Fraser
7 * Multi-process extensions Copyright (c) 2004, Steven Smith
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation; or, when distributed
12 * separately from the Linux kernel or incorporated into other
13 * software packages, subject to the following license:
15 * Permission is hereby granted, free of charge, to any person obtaining a copy
16 * of this source file (the "Software"), to deal in the Software without
17 * restriction, including without limitation the rights to use, copy, modify,
18 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
19 * and to permit persons to whom the Software is furnished to do so, subject to
20 * the following conditions:
22 * The above copyright notice and this permission notice shall be included in
23 * all copies or substantial portions of the Software.
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
28 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
34 #include <linux/module.h>
35 #include <linux/kernel.h>
36 #include <linux/sched.h>
37 #include <linux/slab.h>
38 #include <linux/string.h>
39 #include <linux/errno.h>
41 #include <linux/errno.h>
42 #include <linux/miscdevice.h>
43 #include <linux/major.h>
44 #include <linux/proc_fs.h>
45 #include <linux/stat.h>
46 #include <linux/poll.h>
47 #include <linux/irq.h>
48 #include <linux/init.h>
49 #include <linux/gfp.h>
50 #include <linux/mutex.h>
51 #include <xen/evtchn.h>
52 #include <xen/public/evtchn.h>
54 struct per_user_data {
55 /* Notification ring, accessed via /dev/xen/evtchn. */
56 #define EVTCHN_RING_SIZE (PAGE_SIZE / sizeof(evtchn_port_t))
57 #define EVTCHN_RING_MASK(_i) ((_i)&(EVTCHN_RING_SIZE-1))
59 unsigned int ring_cons, ring_prod, ring_overflow;
60 struct mutex ring_cons_mutex; /* protect against concurrent readers */
62 /* Processes wait on this queue when ring is empty. */
63 wait_queue_head_t evtchn_wait;
64 struct fasync_struct *evtchn_async_queue;
67 /* Who's bound to each port? */
68 static struct per_user_data *port_user[NR_EVENT_CHANNELS];
69 static spinlock_t port_user_lock;
71 void evtchn_device_upcall(int port)
73 struct per_user_data *u;
75 spin_lock(&port_user_lock);
80 if ((u = port_user[port]) != NULL) {
81 if ((u->ring_prod - u->ring_cons) < EVTCHN_RING_SIZE) {
82 u->ring[EVTCHN_RING_MASK(u->ring_prod)] = port;
83 if (u->ring_cons == u->ring_prod++) {
84 wake_up_interruptible(&u->evtchn_wait);
85 kill_fasync(&u->evtchn_async_queue,
93 spin_unlock(&port_user_lock);
96 static ssize_t evtchn_read(struct file *file, char __user *buf,
97 size_t count, loff_t *ppos)
100 unsigned int c, p, bytes1 = 0, bytes2 = 0;
101 struct per_user_data *u = file->private_data;
103 /* Whole number of ports. */
104 count &= ~(sizeof(evtchn_port_t)-1);
109 if (count > PAGE_SIZE)
113 mutex_lock(&u->ring_cons_mutex);
116 if (u->ring_overflow)
119 if ((c = u->ring_cons) != (p = u->ring_prod))
122 mutex_unlock(&u->ring_cons_mutex);
124 if (file->f_flags & O_NONBLOCK)
127 rc = wait_event_interruptible(
128 u->evtchn_wait, u->ring_cons != u->ring_prod);
133 /* Byte lengths of two chunks. Chunk split (if any) is at ring wrap. */
134 if (((c ^ p) & EVTCHN_RING_SIZE) != 0) {
135 bytes1 = (EVTCHN_RING_SIZE - EVTCHN_RING_MASK(c)) *
136 sizeof(evtchn_port_t);
137 bytes2 = EVTCHN_RING_MASK(p) * sizeof(evtchn_port_t);
139 bytes1 = (p - c) * sizeof(evtchn_port_t);
143 /* Truncate chunks according to caller's maximum byte count. */
144 if (bytes1 > count) {
147 } else if ((bytes1 + bytes2) > count) {
148 bytes2 = count - bytes1;
152 if (copy_to_user(buf, &u->ring[EVTCHN_RING_MASK(c)], bytes1) ||
154 copy_to_user(&buf[bytes1], &u->ring[0], bytes2)))
157 u->ring_cons += (bytes1 + bytes2) / sizeof(evtchn_port_t);
158 rc = bytes1 + bytes2;
161 mutex_unlock(&u->ring_cons_mutex);
165 static ssize_t evtchn_write(struct file *file, const char __user *buf,
166 size_t count, loff_t *ppos)
169 evtchn_port_t *kbuf = (evtchn_port_t *)__get_free_page(GFP_KERNEL);
170 struct per_user_data *u = file->private_data;
175 /* Whole number of ports. */
176 count &= ~(sizeof(evtchn_port_t)-1);
182 if (count > PAGE_SIZE)
186 if (copy_from_user(kbuf, buf, count) != 0)
189 spin_lock_irq(&port_user_lock);
190 for (i = 0; i < (count/sizeof(evtchn_port_t)); i++)
191 if ((kbuf[i] < NR_EVENT_CHANNELS) && (port_user[kbuf[i]] == u))
192 unmask_evtchn(kbuf[i]);
193 spin_unlock_irq(&port_user_lock);
198 free_page((unsigned long)kbuf);
202 static void evtchn_bind_to_user(struct per_user_data *u, int port)
204 spin_lock_irq(&port_user_lock);
205 BUG_ON(port_user[port] != NULL);
208 spin_unlock_irq(&port_user_lock);
211 static int evtchn_ioctl(struct inode *inode, struct file *file,
212 unsigned int cmd, unsigned long arg)
215 struct per_user_data *u = file->private_data;
216 void __user *uarg = (void __user *) arg;
219 case IOCTL_EVTCHN_BIND_VIRQ: {
220 struct ioctl_evtchn_bind_virq bind;
221 struct evtchn_bind_virq bind_virq;
224 if (copy_from_user(&bind, uarg, sizeof(bind)))
227 bind_virq.virq = bind.virq;
229 rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
235 evtchn_bind_to_user(u, rc);
239 case IOCTL_EVTCHN_BIND_INTERDOMAIN: {
240 struct ioctl_evtchn_bind_interdomain bind;
241 struct evtchn_bind_interdomain bind_interdomain;
244 if (copy_from_user(&bind, uarg, sizeof(bind)))
247 bind_interdomain.remote_dom = bind.remote_domain;
248 bind_interdomain.remote_port = bind.remote_port;
249 rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
254 rc = bind_interdomain.local_port;
255 evtchn_bind_to_user(u, rc);
259 case IOCTL_EVTCHN_BIND_UNBOUND_PORT: {
260 struct ioctl_evtchn_bind_unbound_port bind;
261 struct evtchn_alloc_unbound alloc_unbound;
264 if (copy_from_user(&bind, uarg, sizeof(bind)))
267 alloc_unbound.dom = DOMID_SELF;
268 alloc_unbound.remote_dom = bind.remote_domain;
269 rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
274 rc = alloc_unbound.port;
275 evtchn_bind_to_user(u, rc);
279 case IOCTL_EVTCHN_UNBIND: {
280 struct ioctl_evtchn_unbind unbind;
281 struct evtchn_close close;
285 if (copy_from_user(&unbind, uarg, sizeof(unbind)))
289 if (unbind.port >= NR_EVENT_CHANNELS)
292 spin_lock_irq(&port_user_lock);
295 if (port_user[unbind.port] != u) {
296 spin_unlock_irq(&port_user_lock);
300 port_user[unbind.port] = NULL;
301 mask_evtchn(unbind.port);
303 spin_unlock_irq(&port_user_lock);
305 close.port = unbind.port;
306 ret = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
313 case IOCTL_EVTCHN_NOTIFY: {
314 struct ioctl_evtchn_notify notify;
317 if (copy_from_user(¬ify, uarg, sizeof(notify)))
320 if (notify.port >= NR_EVENT_CHANNELS) {
322 } else if (port_user[notify.port] != u) {
325 notify_remote_via_evtchn(notify.port);
331 case IOCTL_EVTCHN_RESET: {
332 /* Initialise the ring to empty. Clear errors. */
333 mutex_lock(&u->ring_cons_mutex);
334 spin_lock_irq(&port_user_lock);
335 u->ring_cons = u->ring_prod = u->ring_overflow = 0;
336 spin_unlock_irq(&port_user_lock);
337 mutex_unlock(&u->ring_cons_mutex);
350 static unsigned int evtchn_poll(struct file *file, poll_table *wait)
352 unsigned int mask = POLLOUT | POLLWRNORM;
353 struct per_user_data *u = file->private_data;
355 poll_wait(file, &u->evtchn_wait, wait);
356 if (u->ring_cons != u->ring_prod)
357 mask |= POLLIN | POLLRDNORM;
358 if (u->ring_overflow)
363 static int evtchn_fasync(int fd, struct file *filp, int on)
365 struct per_user_data *u = filp->private_data;
366 return fasync_helper(fd, filp, on, &u->evtchn_async_queue);
369 static int evtchn_open(struct inode *inode, struct file *filp)
371 struct per_user_data *u;
373 if ((u = kmalloc(sizeof(*u), GFP_KERNEL)) == NULL)
376 memset(u, 0, sizeof(*u));
377 init_waitqueue_head(&u->evtchn_wait);
379 u->ring = (evtchn_port_t *)__get_free_page(GFP_KERNEL);
380 if (u->ring == NULL) {
385 mutex_init(&u->ring_cons_mutex);
387 filp->private_data = u;
392 static int evtchn_release(struct inode *inode, struct file *filp)
395 struct per_user_data *u = filp->private_data;
396 struct evtchn_close close;
398 spin_lock_irq(&port_user_lock);
400 free_page((unsigned long)u->ring);
402 for (i = 0; i < NR_EVENT_CHANNELS; i++) {
404 if (port_user[i] != u)
411 ret = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
415 spin_unlock_irq(&port_user_lock);
422 static const struct file_operations evtchn_fops = {
423 .owner = THIS_MODULE,
425 .write = evtchn_write,
426 .ioctl = evtchn_ioctl,
428 .fasync = evtchn_fasync,
430 .release = evtchn_release,
433 static struct miscdevice evtchn_miscdev = {
434 .minor = MISC_DYNAMIC_MINOR,
436 .fops = &evtchn_fops,
439 static int __init evtchn_init(void)
443 if (!is_running_on_xen())
446 spin_lock_init(&port_user_lock);
447 memset(port_user, 0, sizeof(port_user));
449 /* Create '/dev/misc/evtchn'. */
450 err = misc_register(&evtchn_miscdev);
452 printk(KERN_ALERT "Could not register /dev/misc/evtchn\n");
456 printk("Event-channel device installed.\n");
461 static void evtchn_cleanup(void)
463 misc_deregister(&evtchn_miscdev);
466 module_init(evtchn_init);
467 module_exit(evtchn_cleanup);
469 MODULE_LICENSE("Dual BSD/GPL");