/* /dev/xeno/evtchn resides at device number major=10, minor=200 */
#define EVTCHN_MINOR 200
+/* /dev/xeno/evtchn ioctls: */
+/* EVTCHN_RESET: Clear and reinit the event buffer. Clear error condition. */
+#define EVTCHN_RESET _IO('E', 1)
+
/* NB. This must be shared amongst drivers if more things go in /dev/xeno */
static devfs_handle_t xeno_dev_dir;
static unsigned long evtchn_dev_inuse;
/* Notification ring, accessed via /dev/xeno/evtchn. */
+#define RING_SIZE 2048 /* 2048 16-bit entries */
+#define RING_MASK(_i) ((_i)&(RING_SIZE-1))
static u16 *ring;
-static unsigned int ring_cons, ring_prod;
+static unsigned int ring_cons, ring_prod, ring_overflow;
/* Processes wait on this queue via /dev/xeno/evtchn when ring is empty. */
static DECLARE_WAIT_QUEUE_HEAD(evtchn_wait);
}
else if ( ring != NULL )
{
- ring[ring_prod] = (u16)(port | port_subtype);
- if ( ring_cons == ring_prod++ )
+ if ( (ring_prod - ring_cons) < RING_SIZE )
+ {
+ ring[RING_MASK(ring_prod)] = (u16)(port | port_subtype);
+ if ( ring_cons == ring_prod++ )
+ {
+ wake_up_interruptible(&evtchn_wait);
+ kill_fasync(&evtchn_async_queue, SIGIO, POLL_IN);
+ }
+ }
+ else
{
- wake_up_interruptible(&evtchn_wait);
- kill_fasync(&evtchn_async_queue, SIGIO, POLL_IN);
+ ring_overflow = 1;
}
}
}
spin_unlock_irqrestore(&lock, flags);
}
+static void __evtchn_reset_buffer_ring(void)
+{
+ u32 m;
+ unsigned int i, j;
+
+ /* Initialise the ring with currently outstanding notifications. */
+ ring_cons = ring_prod = ring_overflow = 0;
+
+ for ( i = 0; i < 32; i++ )
+ {
+ m = pend_outstanding[i];
+ while ( (j = ffs(m)) != 0 )
+ {
+ m &= ~(1 << --j);
+ if ( rx_fns[(i * 32) + j] == NULL )
+ ring[ring_prod++] = (u16)(((i * 32) + j) | PORT_NORMAL);
+ }
+
+ m = disc_outstanding[i];
+ while ( (j = ffs(m)) != 0 )
+ {
+ m &= ~(1 << --j);
+ if ( rx_fns[(i * 32) + j] == NULL )
+ ring[ring_prod++] = (u16)(((i * 32) + j) | PORT_DISCONNECT);
+ }
+ }
+}
+
static ssize_t evtchn_read(struct file *file, char *buf,
size_t count, loff_t *ppos)
{
int rc;
+ unsigned int c, p, bytes1 = 0, bytes2 = 0;
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(&evtchn_wait, &wait);
+ if ( (count <= 0) || (count > PAGE_SIZE) || ((count&1) != 0) )
+ {
+ rc = -EINVAL;
+ goto out;
+ }
+
for ( ; ; )
{
set_current_state(TASK_INTERRUPTIBLE);
- if ( ring_cons != ring_prod )
+ if ( (c = ring_cons) != (p = ring_prod) )
break;
+ if ( ring_overflow )
+ {
+ rc = -EFBIG;
+ goto out;
+ }
+
if ( file->f_flags & O_NONBLOCK )
{
rc = -EAGAIN;
schedule();
}
- rc = -EINVAL;
- if ( count >= sizeof(ring_prod) )
- rc = put_user(ring_prod, (unsigned int *)buf);
- if ( rc == 0 )
- rc = sizeof(ring_prod);
+ rc = -EFAULT;
+
+ /* Byte length of first chunk. May be truncated by ring wrap. */
+ if ( ((c ^ p) & RING_SIZE) != 0 )
+ bytes1 = (RING_SIZE - RING_MASK(c)) * sizeof(u16);
+ else
+ bytes1 = (p - c) * sizeof(u16);
+
+ /* Further truncate chunk length according to caller's maximum count. */
+ if ( bytes1 > count )
+ bytes1 = count;
+
+ /* Copy the first chunk. */
+ if ( copy_to_user(buf, &ring[c], bytes1) != 0 )
+ goto out;
+
+ /* More bytes to copy? */
+ if ( count > bytes1 )
+ {
+ bytes2 = RING_MASK(p) * sizeof(u16);
+ if ( bytes2 > count )
+ bytes2 = count;
+ if ( (bytes2 != 0) && copy_to_user(&buf[bytes1], &ring[0], bytes2) )
+ goto out;
+ }
+
+ ring_cons = (bytes1 + bytes2) / sizeof(u16);
+
+ rc = bytes1 + bytes2;
out:
__set_current_state(TASK_RUNNING);
static ssize_t evtchn_write(struct file *file, const char *buf,
size_t count, loff_t *ppos)
{
- int rc = -EINVAL;
- unsigned int new_cons = 0;
+ int rc, i;
+ u16 *kbuf = (u16 *)get_free_page(GFP_KERNEL);
- if ( count >= sizeof(new_cons) )
- rc = get_user(new_cons, (unsigned int *)buf);
+ if ( kbuf == NULL )
+ return -ENOMEM;
- if ( rc != 0 )
- return rc;
+ if ( (count <= 0) || (count > PAGE_SIZE) || ((count&1) != 0) )
+ {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ if ( copy_from_user(kbuf, buf, count) != 0 )
+ {
+ rc = -EFAULT;
+ goto out;
+ }
- rc = sizeof(new_cons);
+ for ( i = 0; i < (count/2); i++ )
+ evtchn_clear_port(kbuf[i]);
- while ( ring_cons != new_cons )
- evtchn_clear_port(ring[ring_cons++]);
+ rc = count;
+ out:
+ free_page((unsigned long)kbuf);
return rc;
}
+static int evtchn_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ if ( cmd != EVTCHN_RESET )
+ return -EINVAL;
+
+ spin_lock_irq(&lock);
+ __evtchn_reset_buffer_ring();
+ spin_unlock_irq(&lock);
+
+ return 0;
+}
+
static unsigned int evtchn_poll(struct file *file, poll_table *wait)
{
unsigned int mask = POLLOUT | POLLWRNORM;
poll_wait(file, &evtchn_wait, wait);
if ( ring_cons != ring_prod )
mask |= POLLIN | POLLRDNORM;
+ if ( ring_overflow )
+ mask = POLLERR;
return mask;
}
-static int evtchn_mmap(struct file *file, struct vm_area_struct *vma)
-{
- /* Caller must map a single page of memory from 'file offset' zero. */
- if ( (vma->vm_pgoff != 0) || ((vma->vm_end - vma->vm_start) != PAGE_SIZE) )
- return -EINVAL;
-
- /* Not a pageable area. */
- vma->vm_flags |= VM_RESERVED;
-
- if ( remap_page_range(vma->vm_start, 0, PAGE_SIZE, vma->vm_page_prot) )
- return -EAGAIN;
-
- return 0;
-}
-
static int evtchn_fasync(int fd, struct file *filp, int on)
{
return fasync_helper(fd, filp, on, &evtchn_async_queue);
static int evtchn_open(struct inode *inode, struct file *filp)
{
- u16 *_ring;
- u32 m;
- unsigned int i, j;
+ u16 *_ring;
if ( test_and_set_bit(0, &evtchn_dev_inuse) )
return -EBUSY;
return -ENOMEM;
spin_lock_irq(&lock);
-
ring = _ring;
-
- /* Initialise the ring with currently outstanding notifications. */
- ring_cons = ring_prod = 0;
- for ( i = 0; i < 32; i++ )
- {
- m = pend_outstanding[i];
- while ( (j = ffs(m)) != 0 )
- {
- m &= ~(1 << --j);
- if ( rx_fns[(i * 32) + j] == NULL )
- ring[ring_prod++] = (u16)(((i * 32) + j) | PORT_NORMAL);
- }
-
- m = disc_outstanding[i];
- while ( (j = ffs(m)) != 0 )
- {
- m &= ~(1 << --j);
- if ( rx_fns[(i * 32) + j] == NULL )
- ring[ring_prod++] = (u16)(((i * 32) + j) | PORT_DISCONNECT);
- }
- }
-
+ __evtchn_reset_buffer_ring();
spin_unlock_irq(&lock);
MOD_INC_USE_COUNT;
owner: THIS_MODULE,
read: evtchn_read,
write: evtchn_write,
+ ioctl: evtchn_ioctl,
poll: evtchn_poll,
- mmap: evtchn_mmap,
fasync: evtchn_fasync,
open: evtchn_open,
release: evtchn_release
projects / xen.git / commitdiff