3a6d1fcf9c
Log:
- merge in latest xenbus from dfr's xenhvm
- fix race condition in xs_read_reply by converting tsleep to mtx_sleep
Log:
unmask evtchn in bind_{virq, ipi}_to_irq
Log:
- remove code for handling case of not being able to sleep
- eliminate tsleep - make sleeps atomic
395 lines
8.0 KiB
C
395 lines
8.0 KiB
C
/******************************************************************************
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* evtchn.c
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*
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* Xenolinux driver for receiving and demuxing event-channel signals.
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*
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* Copyright (c) 2004, K A Fraser
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/uio.h>
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#include <sys/bus.h>
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#include <sys/malloc.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/selinfo.h>
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#include <sys/poll.h>
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#include <sys/conf.h>
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#include <sys/fcntl.h>
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#include <sys/ioccom.h>
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#include <machine/cpufunc.h>
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#include <machine/intr_machdep.h>
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#include <machine/xen/xen-os.h>
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#include <xen/xen_intr.h>
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#include <machine/bus.h>
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#include <sys/rman.h>
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#include <machine/resource.h>
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#include <machine/xen/synch_bitops.h>
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#include <xen/hypervisor.h>
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#include <xen/evtchn.h>
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typedef struct evtchn_sotfc {
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struct selinfo ev_rsel;
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} evtchn_softc_t;
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#ifdef linuxcrap
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/* NB. This must be shared amongst drivers if more things go in /dev/xen */
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static devfs_handle_t xen_dev_dir;
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#endif
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/* Only one process may open /dev/xen/evtchn at any time. */
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static unsigned long evtchn_dev_inuse;
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/* Notification ring, accessed via /dev/xen/evtchn. */
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#define EVTCHN_RING_SIZE 2048 /* 2048 16-bit entries */
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#define EVTCHN_RING_MASK(_i) ((_i)&(EVTCHN_RING_SIZE-1))
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static uint16_t *ring;
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static unsigned int ring_cons, ring_prod, ring_overflow;
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/* Which ports is user-space bound to? */
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static uint32_t bound_ports[32];
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/* Unique address for processes to sleep on */
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static void *evtchn_waddr = ˚
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static struct mtx lock, upcall_lock;
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static d_read_t evtchn_read;
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static d_write_t evtchn_write;
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static d_ioctl_t evtchn_ioctl;
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static d_poll_t evtchn_poll;
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static d_open_t evtchn_open;
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static d_close_t evtchn_close;
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void
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evtchn_device_upcall(int port)
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{
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mtx_lock(&upcall_lock);
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mask_evtchn(port);
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clear_evtchn(port);
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if ( ring != NULL ) {
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if ( (ring_prod - ring_cons) < EVTCHN_RING_SIZE ) {
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ring[EVTCHN_RING_MASK(ring_prod)] = (uint16_t)port;
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if ( ring_cons == ring_prod++ ) {
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wakeup(evtchn_waddr);
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}
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}
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else {
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ring_overflow = 1;
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}
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}
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mtx_unlock(&upcall_lock);
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}
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static void
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__evtchn_reset_buffer_ring(void)
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{
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/* Initialise the ring to empty. Clear errors. */
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ring_cons = ring_prod = ring_overflow = 0;
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}
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static int
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evtchn_read(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int rc;
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unsigned int count, c, p, sst = 0, bytes1 = 0, bytes2 = 0;
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count = uio->uio_resid;
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count &= ~1; /* even number of bytes */
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if ( count == 0 )
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{
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rc = 0;
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goto out;
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}
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if ( count > PAGE_SIZE )
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count = PAGE_SIZE;
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for ( ; ; ) {
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if ( (c = ring_cons) != (p = ring_prod) )
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break;
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if ( ring_overflow ) {
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rc = EFBIG;
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goto out;
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}
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if (sst != 0) {
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rc = EINTR;
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goto out;
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}
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/* PCATCH == check for signals before and after sleeping
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* PWAIT == priority of waiting on resource
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*/
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sst = tsleep(evtchn_waddr, PWAIT|PCATCH, "evchwt", 10);
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}
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/* Byte lengths of two chunks. Chunk split (if any) is at ring wrap. */
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if ( ((c ^ p) & EVTCHN_RING_SIZE) != 0 ) {
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bytes1 = (EVTCHN_RING_SIZE - EVTCHN_RING_MASK(c)) * sizeof(uint16_t);
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bytes2 = EVTCHN_RING_MASK(p) * sizeof(uint16_t);
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}
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else {
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bytes1 = (p - c) * sizeof(uint16_t);
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bytes2 = 0;
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}
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/* Truncate chunks according to caller's maximum byte count. */
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if ( bytes1 > count ) {
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bytes1 = count;
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bytes2 = 0;
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}
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else if ( (bytes1 + bytes2) > count ) {
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bytes2 = count - bytes1;
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}
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if ( uiomove(&ring[EVTCHN_RING_MASK(c)], bytes1, uio) ||
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((bytes2 != 0) && uiomove(&ring[0], bytes2, uio)))
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/* keeping this around as its replacement is not equivalent
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* copyout(&ring[0], &buf[bytes1], bytes2)
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*/
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{
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rc = EFAULT;
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goto out;
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}
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ring_cons += (bytes1 + bytes2) / sizeof(uint16_t);
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rc = bytes1 + bytes2;
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out:
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return rc;
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}
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static int
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evtchn_write(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int rc, i, count;
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count = uio->uio_resid;
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uint16_t *kbuf = (uint16_t *)malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
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if ( kbuf == NULL )
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return ENOMEM;
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count &= ~1; /* even number of bytes */
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if ( count == 0 ) {
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rc = 0;
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goto out;
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}
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if ( count > PAGE_SIZE )
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count = PAGE_SIZE;
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if ( uiomove(kbuf, count, uio) != 0 ) {
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rc = EFAULT;
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goto out;
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}
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mtx_lock_spin(&lock);
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for ( i = 0; i < (count/2); i++ )
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if ( test_bit(kbuf[i], &bound_ports[0]) )
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unmask_evtchn(kbuf[i]);
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mtx_unlock_spin(&lock);
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rc = count;
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out:
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free(kbuf, M_DEVBUF);
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return rc;
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}
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static int
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evtchn_ioctl(struct cdev *dev, unsigned long cmd, caddr_t arg,
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int mode, struct thread *td __unused)
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{
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int rc = 0;
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mtx_lock_spin(&lock);
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switch ( cmd )
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{
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case EVTCHN_RESET:
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__evtchn_reset_buffer_ring();
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break;
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case EVTCHN_BIND:
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if ( !synch_test_and_set_bit((int)arg, &bound_ports[0]) )
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unmask_evtchn((int)arg);
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else
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rc = EINVAL;
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break;
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case EVTCHN_UNBIND:
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if ( synch_test_and_clear_bit((int)arg, &bound_ports[0]) )
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mask_evtchn((int)arg);
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else
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rc = EINVAL;
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break;
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default:
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rc = ENOSYS;
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break;
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}
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mtx_unlock_spin(&lock);
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return rc;
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}
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static int
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evtchn_poll(struct cdev *dev, int poll_events, struct thread *td)
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{
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evtchn_softc_t *sc;
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unsigned int mask = POLLOUT | POLLWRNORM;
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sc = dev->si_drv1;
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if ( ring_cons != ring_prod )
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mask |= POLLIN | POLLRDNORM;
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else if ( ring_overflow )
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mask = POLLERR;
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else
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selrecord(td, &sc->ev_rsel);
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return mask;
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}
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static int
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evtchn_open(struct cdev *dev, int flag, int otyp, struct thread *td)
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{
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uint16_t *_ring;
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if (flag & O_NONBLOCK)
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return EBUSY;
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if ( synch_test_and_set_bit(0, &evtchn_dev_inuse) )
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return EBUSY;
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if ( (_ring = (uint16_t *)malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK)) == NULL )
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return ENOMEM;
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mtx_lock_spin(&lock);
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ring = _ring;
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__evtchn_reset_buffer_ring();
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mtx_unlock_spin(&lock);
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return 0;
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}
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static int
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evtchn_close(struct cdev *dev, int flag, int otyp, struct thread *td __unused)
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{
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int i;
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mtx_lock_spin(&lock);
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if (ring != NULL) {
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free(ring, M_DEVBUF);
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ring = NULL;
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}
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for ( i = 0; i < NR_EVENT_CHANNELS; i++ )
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if ( synch_test_and_clear_bit(i, &bound_ports[0]) )
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mask_evtchn(i);
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mtx_unlock_spin(&lock);
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evtchn_dev_inuse = 0;
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return 0;
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}
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static struct cdevsw evtchn_devsw = {
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d_version: D_VERSION,
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d_open: evtchn_open,
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d_close: evtchn_close,
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d_read: evtchn_read,
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d_write: evtchn_write,
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d_ioctl: evtchn_ioctl,
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d_poll: evtchn_poll,
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d_name: "evtchn",
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d_flags: 0,
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};
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/* XXX - if this device is ever supposed to support use by more than one process
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* this global static will have to go away
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*/
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static struct cdev *evtchn_dev;
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static int
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evtchn_dev_init(void *dummy __unused)
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{
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/* XXX I believe we don't need these leaving them here for now until we
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* have some semblance of it working
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*/
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mtx_init(&upcall_lock, "evtchup", NULL, MTX_DEF);
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/* (DEVFS) create '/dev/misc/evtchn'. */
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evtchn_dev = make_dev(&evtchn_devsw, 0, UID_ROOT, GID_WHEEL, 0600, "xen/evtchn");
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mtx_init(&lock, "evch", NULL, MTX_SPIN | MTX_NOWITNESS);
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evtchn_dev->si_drv1 = malloc(sizeof(evtchn_softc_t), M_DEVBUF, M_WAITOK);
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bzero(evtchn_dev->si_drv1, sizeof(evtchn_softc_t));
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/* XXX I don't think we need any of this rubbish */
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#if 0
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if ( err != 0 )
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{
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printk(KERN_ALERT "Could not register /dev/misc/evtchn\n");
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return err;
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}
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/* (DEVFS) create directory '/dev/xen'. */
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xen_dev_dir = devfs_mk_dir(NULL, "xen", NULL);
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/* (DEVFS) &link_dest[pos] == '../misc/evtchn'. */
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pos = devfs_generate_path(evtchn_miscdev.devfs_handle,
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&link_dest[3],
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sizeof(link_dest) - 3);
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if ( pos >= 0 )
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strncpy(&link_dest[pos], "../", 3);
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/* (DEVFS) symlink '/dev/xen/evtchn' -> '../misc/evtchn'. */
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(void)devfs_mk_symlink(xen_dev_dir,
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"evtchn",
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DEVFS_FL_DEFAULT,
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&link_dest[pos],
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&symlink_handle,
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NULL);
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/* (DEVFS) automatically destroy the symlink with its destination. */
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devfs_auto_unregister(evtchn_miscdev.devfs_handle, symlink_handle);
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#endif
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printk("Event-channel device installed.\n");
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return 0;
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}
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SYSINIT(evtchn_dev_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, evtchn_dev_init, NULL);
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